Hamburgers are intensely proud of their tunnel beneath the river.

Housing the groundbreaking maps and globes of Gerard Mercator.

A 14th-century fortified keep showcases the masterpieces of an ingenious 20th-century clockmaker.

This former Masonic lodge has been transformed into part museum, part bar, all awesome.

Artfully arranged bones of 5,800 Austrians.

This former insane asylum now holds a pathological anatomy museum.

The beautiful baroque library of the Hapsburg empire.

The Lone Star plaque hangs in a bombed-out bunker in Normandy to honor a Texan colonel's heroic actions on D-Day.

A resort destroyed by a mysterious bombing offers visitors only its remains and the riddle behind it's demise.

Underneath a chalk hill in France lies what Hitler hoped would be the underground launching base for a devastating new weapon.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

This unique bridge physically lifts a piece of the road into the air to let boats pass by.

The world's only museum devoted to the wonders of fluorescence.

This Denmark theme park is part family attraction, part experimental archaeology project.

The farthest northwesterly point of the British mainland is one of the most remote places in the Scottish Highlands.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

Through seven years of burglary, bereavement, and bad luck, a gentleman kept his word by saying none.

This informal museum is a magical trove of anonymous art collected from car boots and flea markets.

If your school was decorated with trippy graffiti, served ambrosial coffee, and was frequented by mimes, it might have been similar to this groovy cafe.

This Iron Age hill fort remained hidden until a series of storms revealed its history.

These curious rocks located in the Lake District include several strange inscriptions of famous names.

These upturned herring boats make nifty storage sheds for fishing goods.