A dark tunnel leads to a striking white crater that seems to be from another planet.

Explore the atmospheric ruins of an abandoned convent in the dense forests of Mexico's first national park.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

This crumbling Art Deco movie palace in Mexico City has been abandoned for two decades.

A museum in the former home of Marxist revolutionary Leon Trotsky.

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

Mexico's astounding mummy museum with "the world's smallest mummy."

The only castle in North America to ever house European sovereigns.

A quirky and charming restaurant founded by artists.

North America's oldest quarantine facility was built in response to Philadelphia's 1793 yellow fever outbreak.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

A rare view of a preserved Victorian science museum.

Pennsylvanian mass grave and possibly mass murder.