A student driver's nightmare.

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

This concrete residential area doubles as an open-air gallery.

Hidden beneath the streets of London is a secret subway that only carried mail.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

An eerie, derelict amusement park in Berlin.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A kaleidoscopic warehouse-maze of handmade neon signs.

A Boeing mechanic and his wife leave a whimsical, stone sculptured garden as their legacy.

The Denny Substation has been called "the coolest substation in the world" and sits in a densely populated Seattle neighborhood.

This gold-winged spire celebrates the first true flight around the world.

Granting the right of way to ships over surface traffic since 1917.

Always a new use for this old building.

This Puget Sound military post has a long, turbulent history as a gateway to the Pacific.

This tiny home built on revenge appears to be scarcely wider than a Volkswagen.

This Cold War siren is one off the last of its kind still standing with its immensely powerful original horn.

Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

Activists are fighting to preserve these unfinished highway ramps as a tribute to the citizen revolt that halted their construction decades ago.

Spanning an elevation of 160 feet and containing 388 steps, this is Seattle's longest staircase.

A "sinister, whimsical, tacky, and really orange" public art installation hidden under a Seattle bridge.

The tech giant built three enormous glass orbs in Seattle so employees could work inside a rainforest greenhouse.

A beautiful final resting place for some of the noteworthy deceased.