Trace the globe-spanning journey of coffee as it goes from plant to brew, and the complex infrastructure that makes it possible. -- How many people does it take to make a cup of coffee? For many of us, all it takes is a short walk and a quick pour. But this simple staple is the result of a globe-spanning process whose cost and complexity are far greater than you might imagine. AJ Jacobs traces the journey of this caffeinated elixir from seed to cup. Lesson by A.J. Jacobs, directed by Biljana Labovic. Animation by Daniella Schnitzer

It’s 1762 BCE. As dawn breaks in the Babylonian city of Sippar, Beltani— a priestess and businesswoman— receives an urgent visit from her brother. He makes a troubling accusation: her tavern keeper has been undermining the business Beltani relies on in her old age. Now she has just a few short hours to find out the truth. Soraya Field Fiorio details a day in the life of a Babylonian naditu. Lesson by Soraya Field Fiorio, directed by Keegan Thornhill.

Princess Savitri was benevolent, brilliant, and bright. Her grace was known throughout the land, and many princes and merchants flocked to her family’s palace to seek her hand in marriage. But upon witnessing her blinding splendor in person, the men lost their nerve. Unimpressed with these suitors, she determined to find a husband herself. Iseult Gillespie tells the tale of Savitri and Satyavan. Lesson by Iseult Gillespie, directed by Jagriti Khirwar & Raghav Arumugam.

In 1967, researchers gathered to answer a long-running scientific question: just how long is a second? It might seem obvious at first. A second is the tick of a clock, the swing of a pendulum, the time it takes to count to one. But how precise are those measurements? And what is that length based on? John Kitching digs into how we scientifically define this fundamental unit of time. Lesson by John Kitching, directed by Tjoff Koong.

Consider a bat that is infected with several deadly viruses, including ones that cause rabies, SARS, and Ebola. While this diagnosis would be lethal for other mammals, the winged wonder is totally unfazed, and may even spend the next 30 years living as if this were totally normal— because for bats, it is. So what’s protecting bats from these dangerous infections? Arinjay Banerjee investigates. Lesson by Arinjay Banerjee, directed by Cabong Studios.

What would happen if one day all of humanity’s artificial satellites suddenly disappeared? Within hours, most of the planet’s traffic would grind to a halt, the world economy would shut down, and most countries would declare a state of emergency. Even in the best-case scenario, our civilization would be set back by decades. So, what are the odds of this actually happening? Moriba Jah investigates. Lesson by Moriba Jah, directed by Darvideo Animation Studio.

Today roads, sidewalks, bridges, and skyscrapers are made of a material called concrete. There’s three tons of it for every person on Earth. It’s also played a surprisingly large role in rising global temperatures over the last century. So, what exactly makes concrete problematic, and what can we do to fix it? Explore how scientists are working to create a cleaner, more sustainable concrete. Directed by Lisa LaBracio. Animation and art direction by Luísa M H Copetti and Hype CG

After a concert, you find it difficult to hear your friend rave about the show. It sounds like they're speaking from across the room, and it’s tough to make out their voice over the ringing in your ears. But, by the next morning, the effect has mostly worn off. So what caused these symptoms? And can you go to concerts without damaging your ears? Heather Malyuk explores the properties of sound. Lesson by Heather Malyuk, directed by Anne Beal.

No matter how we make electricity, it takes up space. Coal requires mines, and plants to convert it into electricity. Nuclear power takes uranium mines, facilities to refine it, a reactor, and a place to store the spent fuel safely. Renewable energy needs wind turbines or solar panels. So how much space would it take to power the whole world? Explore the sustainability of different power sources. Directed by Lisa LaBracio. Animation and art direction by Kevin Herrmann, AIM Creative Studios.

In the 1950s, the discovery of two new drugs sparked what would become a multi-billion dollar market for antidepressants. Neither drug was intended to treat depression at all— many doctors and scientists believed psychotherapy was the only approach to treatment. Neil R. Jeyasingam details the decades-long journey that followed and how it revolutionized our understanding of depression. Lesson by Neil R. Jeyasingam, directed by Skirmanta Jakaitė, Art Shot.

One of these three creatures is thought to possess the world’s most painful insect sting: there’s an ant that forages in rainforest canopies, a bee that protects a hive of delectable honey, and a wasp that paralyzes tarantulas. So which has the nastiest sting? Justin Schmidt describes and ranks the pain inflicted by each insect. Lesson by Justin Schmidt, directed by Nicholas Paim, Alopra Studio.

What’s as big as a polar bear, swallows its prey whole, and swims at forty miles an hour? It’s not a shark or a killer whale... it’s the Atlantic bluefin tuna— the largest and longest-lived of the 15 tuna species. Its unique set of adaptations make it one of the most dominant predators in the ocean. Grantly Galland and Raiana McKinney detail how these fish go from tiny hatchling to ocean giant. Lesson by Grantly Galland and Raiana McKinney, directed by Anna Benner.

A throbbing, pounding headache. Bright zigzagging lines across your field of vision. Sensitivity to light, lingering fatigue, disrupted sleep. While an incapacitating headache is one of the most common symptoms, a migraine can include any of these experiences. So what exactly is a migraine? And what causes it? Marianne Schwarz explores what we know— and don't know— about this complex disorder. Lesson by Marianne Schwarz, directed by Bálint Gelley, CUB Animation.

Many animals need sleep. But all of the threats and demands animals face don’t just go away when it’s time to doze. That’s why a range of birds, mammals, and even humans experience some degree of asymmetrical sleep, where parts of the brain are asleep and other areas are more active. So, how does it work? Masako Tamaki explores how animals' brains remain vigilant even at their most vulnerable. Lesson by Masako Tamaki, directed by Biljana Labović. Animated by Iva Ćirić, designed by Manja Ćirić.

n 1944, amateur astronomer Hisako Koyama’s latest endeavor was sketching the sun’s shifting surface. She spent weeks angling her telescope towards the sun and tracking every change she saw with drawings. Little did she know, these drawings were the start of one of the most important records of solar activity in human history. Alex Gendler details the incredible legacy of Koyama's work. Lesson by Alex Gendler, directed by Martina Meštrović.

You’re traveling deep beneath the ocean’s surface, where faint lights flicker and toothy grins flash. Your mission is to survive these depths and journey to the surface after sundown to feed. And as a hatchetfish, almost every other deep-sea creature is trying to eat you. Can you complete the quest? Philip Renaud and Kenneth Kostel share how to survive the ocean's Twilight Zone. Lesson by Philip Renaud and Kenneth Kostel, directed by Cris Wiegandt. Designed by Bárbara Fonseca Sound design by Claudia Ioana Vasiliu Narrated by Addison Anderson Script Editing by Alex Gendler

We have lots in common with our closest primate relatives. But comparatively, humans seem a bit… underdressed. Instead of thick fur covering our bodies, many of us mainly have hair on top of our heads— and a few other places. So, how did we get so naked? And why do we have hair where we do? Nina G. Jablonski explores the evolution of human hair. Lesson by Nina G. Jablonski, directed by Igor Coric, Artrake Studio.

On sunny days, citizens of ancient Rome could be found exchanging news and gossip while attending to more urgent business at the public latrines. Today, most cultures consider trips to the restroom to be a more private occasion. But even when going alone, our shared sewage infrastructure is one of the most pivotal inventions in human history. Francis de los Reyes shares the history of the toilet. Lesson by Francis de los Reyes, directed by Igor Coric, Artrake Studio.

In 1947, the British viceroy announced that after 200 years of British rule, India would gain independence and be partitioned into Hindu India and Muslim Pakistan. What followed was one of the largest and bloodiest forced migrations in history: an estimated 1 million people lost their lives. What caused this violent aftermath? Haimanti Roy details the lasting legacies of the Partition of India.

Axolotls are one of science’s most studied animals. Why, you ask? These extraordinary salamanders are masters of regeneration: they can flawlessly regenerate body parts ranging from amputated limbs and crushed spines to parts of their eyes and brains. So, how do they do it? And what other secrets are they keeping? Luis Zambrano explores the baffling biology of the axolotl. Lesson by Luis Zambrano, directed by Lizete Upīte.

In 1943, Irena Sendler and Janina Grabowska froze when they heard Gestapo pounding on the front door. Knowing she was minutes from arrest, Irena tossed Janina her most dangerous possession: a glass jar containing the names of over 2,000 Jewish children she’d smuggled to safety from the Warsaw Ghetto. Who was this courageous woman? Iseult Gillespie details the life and legacy of Irena Sendler. Lesson by Iseult Gillespie, directed by Chloé Gérard.

After stalking a cuttlefish, a moray eel finally pounces. As the eel snags the mollusk in its teeth, its prey struggles to escape. But before it can wiggle away, a second set of teeth lunge from the eel’s throat. This adaptation is called a pharyngeal jaw, and is one of the most common adaptations under the sea. Darien Satterfield shares how this incredible skeletal mechanism works. Lesson by Darien Satterfield, directed by Zack Williams.

Towering 85 meters above the Norwegian countryside, Mjøstårnet is the world’s tallest wooden building, made almost entirely from the trees of neighboring forests. But as recently as the end of the 20th century, engineers thought it was impossible to build a wooden building over 6 stories tall. So how do wooden structures like this compare to steel and concrete skyscrapers? Stefan Al investigates. Lesson by Stefan Al, directed by Franz Palomares.

In 1904, Chief Lontulu laid 110 twigs in front of a foreign commission. Every twig represented a person in his village who died because of King Leopold’s brutal regime in the Congo. His testimony joined hundreds of others to help bring an end to one of the greatest atrocities in human history. Georges Nzongola-Ntalaja details the horrific abuses of Leopold’s occupation and looting of the Congo.

After the California Gold Rush of 1848, settlers streamed west to strike it rich. In addition to precious metals, they unearthed another treasure: dinosaur bones. Two wealthy scientists in particular— Othniel Charles Marsh and Edward Drinker Cope— competed to uncover these prehistoric monsters. Lukas Rieppel digs into one of the most notorious scientific feuds in history, known as the Bone Wars. Lesson by Lukas Rieppel, directed by Michael Kalopaidis, Zedem Media.

In March 2020, the COVID-19 pandemic rocked economies worldwide. Millions of people lost their jobs, and many businesses struggled to survive or shut down. Governments responded with some of the largest economic relief packages in history— the US alone spent $2.2 trillion on a first round of relief. So where did all this money come from? Jonathan Smith explores the strategy of quantitative easing. Lesson by Jonathan Smith, directed by Serin İnan, Kozmonot Animation Studio.

While the weather in Iceland is often cold, wet, and windy, a nearly endless supply of heat bubbles away below the surface. In fact, almost every building in the country is heated by geothermal energy in a process with virtually no carbon emissions. So how exactly does this renewable energy work? Jean-Baptiste P. Koehl explores the two primary models for harnessing the planet's natural heat. Lesson by Jean-Baptiste P. Koehl, directed by Charlotte Arene.

Prevailing for around 270 million years and encompassing more than 20,000 distinct species, trilobites are some of the most successful lifeforms in Earth’s history. When they sprung into existence, they were among the most diverse and sophisticated organisms on the planet and so had a unique perspective on the ancient world. Nigel Hughes details the rise and fall of these hardy creatures. Lesson by Nigel Hughes, directed by Zsuzsanna Kreif, The Animation Workshop.

In 2009, a satellite circled Earth, scanning and sorting the wavelengths reflecting off the planet’s surface. Researchers noticed something baffling: an unexpected wavelength of unknown origin. They tried looking at Earth with only this wavelength, and saw the planet covered in a red hue of varying intensity. So, what was going on? Zoe Pierrat explores the science of chlorophyll fluorescence. Lesson by Zoe Pierrat, directed by Denis Chapon, The Animation Workshop.

While searching for a kidney donor, Karen Keegan stumbled upon a mystery. After undergoing genetic testing, it turned out that some of her cells had a completely different set of genes from the others. And this second set of genes belonged to her twin sister— who had never been born. How did this happen? Kayla Mandel Sheets explores the condition known as chimerism. Lesson by Kayla Mandel Sheets, directed by Luísa M H Copetti, Hype CG.

Over 2,500 years ago, one of ancient Greece’s most celebrated popstars and erotic poets enraptured listeners. The singer-songwriter offered a uniquely intimate perspective on love, passion, and longing, and was the first on record to combine the words “bitter” and “sweet,” to describe the ups and downs of romance. So, who was this revered figure? Diane J. Rayor uncovers the writings of Sappho. Lesson by Diane J. Rayor, directed by Amir Houshang Moein.

Inside our cells, each of us has a second set of genes completely separate from our 23 pairs of chromosomes. And this isn’t just true for humans— it’s true of every animal, plant, and fungus on Earth. This second genome belongs to our mitochondria, an organelle inside our cells. So why are they so different from anything else in our bodies? Devin Shuman explores the purpose of mitochondrial DNA. Lesson by Devin Shuman, directed by Luísa M H Copetti, Hype CG.

By the end of the 19th century, nearly 40% of American cars were electric. But these vehicles had a few major problems — early car batteries were expensive and inefficient, and the vehicles were twice the price of a gas-powered car. And so for the next several decades, gas-powered cars dominated the market. Can electric cars reclaim their place on the road? Daniel Sperling and Gil Tal investigate. Lesson by Daniel Sperling and Gil Tal, directed by Lobster Studio.

A ravenous swarm stretches as far as the eye can see. It has no leader or strategic plan; its only goals are to eat, breed, and move on. These are desert locusts— infamous for their capacity for destruction. But most of the time desert locusts are no more dangerous than grasshoppers. So what does it take to turn these harmless insects into a crop-consuming plague? Jeffrey A. Lockwood investigates. Lesson by Jeffrey A. Lockwood, directed by Franz Palomares.

A leather mask that clamps the mouth shut. A cannonball sewn into a soldier’s uniform. A machine that delivers sudden electrical pulses. These were all treatments for a problem that has haunted humanity for millennia: snoring. It might seem harmless, but snoring can be a sign of something more dangerous. So, what exactly causes snoring? Alayna Vaughan digs into the troublesome sleep disorder. Lesson by Alayna Vaughan, directed by Rémi Cans, Boniato Studio.

One day, twin brothers Junajpu and Ixb’alanke discovered their father’s hidden ballgame equipment and began to play. Hearing their vigorous game, the lords of the underworld sent a messenger to challenge the boys to a match. Despite the danger, the twins nevertheless answered the call, making the trek to the great city of Xibalba. Who would emerge victorious? Ilan Stavans shares the Maya myth. Lesson by Ilan Stavans, directed by Arvind Singh Jeena and Nikhita Prabhudesai.

On a reef in the Pacific Ocean, 17,000 camouflage groupers dart about in the cloudy water. It is, in fact, an underwater orgy— turned feeding frenzy. An orgy might seem like a rather flamboyant way to breed, but sex in the sea is a surprisingly inventive affair. So what other sneaky escapades are happening under the sea? Luka Seamus Wright offers a peek beneath the ocean’s covers. Lesson by Luka Seamus Wright, directed by Michelle O'Connell and Lisa Vertudaches. Music and sound by Phil Brookes

A mother honeyguide has placed its chick into a bee-eater’s nest— puncturing all the other eggs in the nest and leaving only its own hatching alive. Over the following weeks, the host parents devotedly care for the hatchling whose mother murdered their offspring. This is brood parasitism, a phenomenon which is especially well-known among birds. Steve Rothstein digs into the evolutionary strategy. Lesson by Steve Rothstein, directed by Mauricio Bueno, Lucy Animation Studio.

Between 1927 and 1941, workers blasted 450,000 tons of rock from a mountainside using chisels, jackhammers, and dynamite. Gradually, they carved out Mount Rushmore. Today, the monument draws nearly 3 million people to South Dakota’s Black Hills every year. But its façade belies a dark history. Ned Blackhawk and Jeffrey D. Means explore the destruction of the sacred Six Grandfathers Mountain. Lesson by Ned Blackhawk and Jeffrey D. Means, directed by Anton Bogaty.

Dig into the engineering of the Hoover Dam, a concrete arch-gravity dam on the Colorado River that supplies water to the US southwest. -- In the early 20th century, the US had expanded from coast to coast, but many cities in the southwest still lacked reliable water sources. The Colorado River's erratic flow and frequent floods made it unreliable for agriculture, and the region’s growing cities needed more energy. So the government decided to build a massive hydroelectric dam. Alex Gendler details the creation of the Hoover Dam. Lesson by Alex Gendler, directed by Jovan Rakic, Artrake Studio.