At this 16th-century monastery in rural Bulgaria, visitors can also spend the night.

This apartment is a true time capsule of local life in Bulgaria during the Soviet regime.

There's an old indoor swimming pool hidden directly underneath the White House Press Briefing Room.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

Largest Roman Catholic church in North America.

There's a crumbling old mansion inside the Smithsonian National Zoo.

A nostalgic bibliographic gem.

A derelict bit of transportation infrastructure hidden in the woods.

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

The world’s first museum dedicated to exploring human rights unleashed a wave of controversy.

A marvel of engineering built to prevent annual floods from devastating the city of Winnipeg.

This little theatre at the end of the Urban Gallery in the Manitoba Museum plays silent films from stars who performed in Winnipeg.

This small enclave plays host to a house, church, and wishing well all composed entirely of recycled glass bottles.

Ancient indigenous sculptures steeped in history and shrouded in mystery.

Down the road from where the Wright brothers lifted off is another flight tribute practically hidden from sight in the woods.

A maritime museum holding the remains of Blackbeard's pirate ship.

A retired tobacco farmer's pet project turned into a sturdy miniature city.

A curious collection of oddities including a lock of Alexander Hamilton's hair and Harry Houdini's ouija board.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

A Bronze age settlement on the Greek island of Santorini might have been the inspiration for Plato's Atlantis.