A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

Press 1 for knock-knock jokes.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

Small ship votives hang from the vaulted ceiling of this port-side church with a Latin inscription on the wall.

A historic Montreal market that was the city's agricultural hub for over century.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

The vaulted ceiling is home to a scurry of “squirrelgoyles.”

The only example of a Paris Métro sign in use at a subway station outside of the French capital. 

The Conduit Road Schoolhouse is one of the last one-room schoolhouses remaining in Washington, D.C.

An enormous pair of straw sandals woven in the traditional way—to keep demons at bay.

These relics of the city's past now exist as a prominent modern feature.

The solemn exterior conceals an opulent interior of this 17th century church.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

Once the home of a hermetic monk, this cave now houses a small church.

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

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

A statue in Budapest's Liberty Square honors the former U.S. president's efforts to end the Cold War.

From cartoon characters to tiny tanks, a guerilla sculptor's little bronze statues are hidden throughout the city of Budapest.

A highly-criticized monument in Budapest has become the site of a makeshift Holocaust memorial.

Also known as Uncle Karl, the beloved bronze copper keeps a watchful eye on St. Stephen’s Basilica while people rub his lucky belly.

A random tree outside a Budapest hotel has become a DIY shrine to the late singer.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.