Walk 2,300 feet above the ground on the "Troll's Tongue."

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A rare octagonal brick beacon on an isolated island in the Baltic.

A cathedral resurrected from the ashes of one of Europe's greatest urban fires.

A long-disputed lighthouse built on the wrong side of a Finnish/Swedish island.

A little-known sculpture park of contemporary environmental art in a Lapland forest.

Finnish lake, and scene of an infamous murder mystery.

Crawling into this primordial cave may feel disconcertingly familiar.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

Menacing or in memoriam, the Silent People and their meaning are left to interpretation.

A subterranean house of worship carved right out of the bedrock.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.

This fantastical icy castle is built anew every winter.

Rent out a glass igloo to watch the Northern Lights like you live in the future.