Military

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.

The remains of the furnace and iron works that produced the massive Hudson River Chain still stand in the woods of New York.

America's second-oldest brick baseball stadium was home to a legendary WWII series that only sailors got to see.

This top-secret nuclear bunker hidden in a Bosnian mountain has been converted to a modern art exhibition space.

The western-most fortress on the Great Wall of China has gone from a strategic stronghold to a kitschy tourist carnival.

This Torino museum honors a soldier who kept the city safe using barrels of exploding gunpowder, losing his life in the process.

The site where Confederate president Jefferson Davis was defeated has been marked with a bust... that leaves that part out.

The site of a concentration camp where inmates were made to take part in one of the largest counterfeiting operations in history is now hauntingly empty.

This amended headstone marks the grave of a participant in one of the most successful military deceptions of all time.

This secret Swiss fortress is disguised as a harmless pink house, complete with fake windows.

This long line of cement defensive wedges is named after the famous chocolate bar for obvious reasons.

Empty, but not abandoned, this cavernous Brooklyn loading dock was once considered the largest individual building in the world.

This evocative New Jersey statue memoralizes the Polish victims of a Soviet massacre.

The secret cells in the basement of the KGB's Estonian "Grey House" have been preserved as a grim Cold War museum.