The last fully functional fortress of Germany's World War II Atlantikwall.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.

A 132-year-old telescope continues to keep watch over the night skies above Providence.

One of the largest refracting telescopes in the world, and the first built specifically for studying astrophysics.

Once the world's most modern observatory, this building is now a private school.

High in the Sacramento Mountains, a facility dedicated to studying the sun.

You can dig up your own crystals in the quartz capital of the world.

The world's largest underwater restaurant is submerged off the southern tip of Norway.

Artists and musicians now rule over this former rail station.

Remnants of cells from the most notorious London prison may lie in the basement of a rare Victorian Gin Palace.

At almost 1,000 years old, this is the oldest known door in all of Britain.

What might be the oldest living tree in London has survived fires, bombings, and estate agents.

Order a salt beef-loaded beigel at any hour of the day or night at this East End institution.

This small museum in a former church crypt contains artifacts of the Elephant Man, Jack the Ripper and Florence Nightingale.

Preserved behind glass, the ruins of a medieval building used to store human remains.

A hat for every occasion can be found in this British Columbia haunt.

The ruins of Vancouver's abandoned heritage railway.

A working steam clock, one of only a few in the world, located in Vancouver's Victorian Gastown.

This quirky piece of naval artillery has been deafening Canadians for over a century.

The block of aged dairy is probably still edible after 2,300 years in a peat bog.

Over a thousand feet beneath the Detroit streets is a subterranean metropolis few are allowed to enter.

This imprint of an old computer keyboard has a unique backstory.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

At high tide, the base of the lighthouse covers practically every inch of the island.