A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

One of Europe's oldest libraries.

This battery powered bell has been ringing since 1840 and is one of the worlds longest running science experiments.

A petite castle folly in the English countryside.

World's largest working waterwheel has been around for over 150 years.

The sign at the garden gate reads: "These Plants Can Kill."

The largest known medieval map of the world.

Rare collection of medieval books under lock and key.

The gloomy ruins that inspired Bram Stoker to bring Dracula to life.

Sidney Scurvy, the interactive computer sailor, takes you on a journey to discover the everyday lives of Cook and his men.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

From Tintin to the Smurfs, Europe's greatest graphic icons are celebrated in a grand Art Noveau gallery.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

An ancient monastery, a locked room, and a mysterious book heist.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

Before the electric telegraph, a chain of stone towers carried messages across France.

Berlin's old airport.

Super-heavy Nazi architectural experiment.

Slaughterhouse Five opens its dank doors to fans of Kurt Vonnegut.

This "floating railway" is one of the world's oldest monorail systems.

The oldest Jewish cemetery in Europe survived Hitler's Germany.

Small museum dedicated to one of the founding fathers of modern astronautics.

An extraordinary mechanical calculator designed by the mathematician and philosopher Gottfried Leibniz.

1898 German railroad depot museum with working engines, steam train excursions, and hands-on displays.