A derelict bit of transportation infrastructure hidden in the woods.

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

A painfully obvious spy house sits right across the street from the Russian Embassy.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

A historic neighborhood church is reborn as a psychedelic arts collective.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

The United States Capitol's former columns still stand.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

There's an exclusive Beefeaters pub hidden in the Tower of London.

Scattered throughout London are ancient remnants of the city's former bounding wall.

This pump on the bad side of Victorian London betrayed a horrifying revelation about the water supply.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

This South London cemetery holds the remains of more than 15,000 people.

This overlooked street light once served as a KGB dead letter box.

An unusual round church in London with a Templar past.

One part local history, 99 parts gruesome haunted house.

The broken skateboards that became a poignant memorial to a murdered skater.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

The world's largest collection of witchcraft regalia.