On top of Gibbet Hill lie the ruins of a lavish turn-of-the-century estate that never quite came to be.

Painstakingly built dioramas sit unnoticed in a Boston office building.

Overgrown ruins of a turn of the century island fort that sees very few visitors.

The only surviving fragment of the lost Narragansett Pier Casino.

You can spend the night as an honorary lighthouse keeper in this quaint, historic beacon.

To avoid the demolition costs this abandoned drawbridge was simply left in the up position.

Mysterious stone tower featured in many alternative histories of the New World.

Abandoned Coast Artillery fort now serves as graffiti canvas and sightseeing vantage point.

A crumbling stone stable and carriage house are all that remain of a manse that was once filled with Egyptian artifacts.

The world's oldest and largest museum of mass transit vehicles.

Designed as a place for patients to take in the scenery, this tower has a dark history.

Once the future of underwater combat, this old sub is now open for visitors to muck around in.

A popular 19th-century natural landmark is now hidden within a sprawling forest.

The only one of New Hampshire's original 14 World War II watchtowers to survive in near-original condition.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.