Amid the sprawling Defense Intelligence Agency Headquarters is one of Washington's least accessible museums.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

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

This abandoned prison castle has become an imposing gallery of graffiti art.

The restored and active Victorian-era final resting place of San Francisco.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.

An "anarchical" no man's land, complete with garbage sculptures and a hobo-run "Landfillian Library."

Bonsai garden in Oakland is curated by the first non-Japanese female bonsai master in the United States.

One of the best absinthe distilleries in the United States.

A crumbling Beaux Arts monument to the Bay Area's age of rail.

A modern mechanical planetary system, part of a 10,000 year clock.

Landbridge created by the South Korean version of Moses.

The world's highest and most dangerous infinity pool lies at the precipice of Victoria Falls.

The tea room that pushed the boundaries of adorable straight into...we can't find the words.

Sniff the Titan Arum's rotting flesh.

Bouncing, delightful, mechanical art at the MIT Museum.

An invitation-only museum of items natural and bizarre, arcane and exotic.

The only theatre in the world constructed specifically for sound movement.

Longtime headquarters of controversial boys' club for the world's wealthiest and most powerful.

A fifth-century temple improbably built into the side of a cliff.