Secrets of the Earth

A series examining the characteristics of the Earth's interior, surface and atmosphere begins with a look at how raindrops are formed.

An examination of tsunamis looks at what causes them, where they happen and how they move from open sea to land.

An examination of tides includes a look at the extreme tidal range of Canada's Bay of Fundy and the tidal bores of Alaska's Turnagain Arm.

A look at volcanoes and how they affect the weather includes an examination of the eruption of Mount Tambora in Indonesia in 1815.

A examination of gravity includes a report on an anomaly in Canada's Hudson Bay and a look at how earthquakes affect Earth's gravitational field.

A look at Earth's ideal position in the solar system that enables it to sustain life.

An examination of Earth's metallic core and how it contributes to a magnetic shield that protects the planet from harmful space radiation.

A look at how snow forms and can result in dangerous blizzards examines researchers' work at Storm Peak Laboratory in Steamboat Springs, Colo.; and snowfall in Syracuse, N.Y., that develops over the Great Lakes.

A look at Earth's unusual places, including underwater ecosystems, subterranean spaces and igneous rock formations.