Explore three battlefield behemoths that command land, sea and air.

Inside access shows how an engineering marvel lifts boats to new heights.

Experts imagine how Washington, DC would look if it were rebuilt today.

Discover why the world's strangest disaster zones were built and abandoned.

New discoveries reveal what really happened in a remote Louisiana swamp.

New discoveries reveal what really happened on the shores of Lake Michigan.

New discoveries reveal why an island with a dark past was built.

Experts reveal the sinister purpose of a strange bunker in Florida.

A castle was the site of horrific murders perpetrated by a countess.

Experts reveal the role towers in Greece played during violent feuds.

Experts reveal why a massive, alien-like fortress was built.

An abandoned prison has evidence of a chaotic riot.

An eerie set of buildings in Paris is evidence of an unspeakable evil.

A notorious dictator's paranoid fantasies created a strange bunker.

An underground labyrinth can warp the mind and turn friend into foe.

An abandoned theme park is home to secrets of a forgotten, imaginary world.