Machines Time Forgot

Eight hundred years ago, the biggest building boom the world had ever seen exploded across Europe. All over the continent rival towns and cities competed with each other to build vast cathedrals that towered higher than any other buildings in Europe. But this craze for Gothic architecture also called for the development of a machine that could raise enormous quantities of stone to extreme heights. A handful of medieval illustrations show a type of giant crane, perched high on the top of these gothic buildings. Powered by people walking inside a large treadwheel, just how did medieval craftsmen build such cranes? This programme attempts to reconstruct the medieval cathedral crane using traditional methods, but not everything goes according to plan.

'Greek fire' has been known for some 1,500 years, ever since it was described in contemporary histories of the Byzantine empire. It was used to save Constantinople in AD 674, when it was attacked by the Muslim fleet. But what was this ancient version of napalm? An expert in ancient metalwork and a Byzantine military historian are among those who try to come up with the correct formula.

On 6 September 1776, American revolutionary David Bushnell watched as his egg-shaped submarine crept to the side of HMS Eagle, with the intention of attaching a mine and blowing it up. More than two centuries later, designers work with personnel at the US Naval Academy to repeat this experiment.

Between the 9th and 7th century BC, Assyrian warrior kings created a great empire in the Middle East. They were helped by their battalions of charioteers - the first that the world had seen. In the 21st century, a carriage-maker, a horse trainer and historians – using only a few existing wall reliefs as guides - try to figure out how the chariots were made.