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

This 18th-century sundial was designed to calculate the date of Easter each year.

This unusual subway stop was originally a real estate office.

A futuristic climate change study is nestled deep within this public land.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

A stargazing sculpture made from the ruins of an iconic telescope.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

This unique sculpture is often overlooked by pedestrians.

A remarkable time capsule of American manufacturing deep in Maryland coal country.

Visitors can sit and study the board with this Estonian chess legend and International Grandmaster.

Indents in the pavement are all that remain from a grisly death machine in Paris.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Ruins of a historic medical facility sits eerily by the water.

Hidden in plain sight on the Hudson River is an abandoned train station where nature has taken over.

From working out of his garage to the James Beard semifinals, one Tucson baker has kept his fan base—and his grains—local.

This giant boulder is sandwiched between apartment complexes in upper Manhattan.

This legendary urban waterfall creates a dazzling display of rainbows.

The only Bahá'í house of worship in North America and one of only a handful worldwide.

The oldest residential street in Europe also features an optical illusion.

This railroad track was so secretive that it was omitted from all maps.

This lower Manhattan bar is set up in an old bank vault that rests beneath a skyscraper that hides even more historic splendor.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

The remains of a century-old mansion that met a fiery demise years after it was deserted.