A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

Famously misunderstood wonder of the ancient world

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

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

One of the best collections of wax anatomical models in the world.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

This series of underground chambers contains Europe's largest subterranean lake that is slowly drained each day.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

Visitors dip into a variety of pools of what was once ice.

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

Artfully arranged bones of 5,800 Austrians.

Each year melting snow turns these Austrian hiking trails into scuba zones.

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

A 22-million-year-old sandstone cave is a natural habitat for award-winning cheese.

A symbol of friendship between the mountainous regions of Switzerland and Bhutan.

A breathtaking bridge that crosses a vast gorge over a river's torrents, and has a tale of a devil architect attached.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.

This lovely little bridge hidden in a Switzerland gorge is essentially a fairytale.

This amazing pedestrian suspension bridge in the Swiss Alps would give Indiana Jones nightmares.

The tallest outdoor elevator in Europe rockets passengers on a dizzyingly precarious ride to the top of a mountain.