This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

A way to take your secrets to someone else's grave.

Records of the dead describe the myriad odd ways people used to die.

The oldest living tree in Manhattan comes shrouded in sinister legend.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

During Prohibition, the U.S. Congress had an "official" bootlegger, with his own Capitol Hill office.

Home to a vast and influential collection of Shakespeareana.

A much-maligned monument to teetotalism.

Obscure Freemasons still live in D.C.’s largest private residence.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

This poor little statue is the most vandalized memorial in Washington.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

When it opened during the final years of the embargo, all the drinks and cigars were free.

The walls of the iconic dome are hollow and have a secret stairway.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

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.

This grand gothic brewery has been pumping out suds for over a hundred years.

An exquisite tunnel of cascading flowers.

Hidden behind mountains in Morocco, a remote town hides a thriving surfing community.

The other side is actually green.

World's largest film studio, where visitors tour the decaying sets that litter the harsh desert environment.

Morocco's Argania trees are infested with nut-hungry goats.