For 20 years, this whale skeleton has been slowly dripping oil on the floor of the museum where it hangs.

On a small Puerto Rican island, banks of secret naval bunkers lie abandoned and filled with piles of office equipment.

This abandoned Belgian fortress is purposefully being left to nature.

The yawning remains of a complex naval fortress still haunt this Australian shore.

This Cold War siren is one off the last of its kind still standing with its immensely powerful original horn.

This monument on Breed's Hill proves that one of the most famous battles of the Revolutionary War is misnamed.

This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

The world's tallest doric column is this Ohio monument to a naval victory in the War of 1812.

These former Cold War launch sites have been preserved for tourists to see where the button might have been pushed.

Australia's only intact colonial warship never saw action before being turned into a scenic wreck.

This sprawling museum holds one man's giant collection of real tanks.

The haunting concrete remains of a Nazi pebble crusher can still be found in this small French commune.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

Read between the lines of the subway map to find the hidden abandoned Civil War fort.

Once defending the city of New Orleans from invasion by sea, this fort faces an uncertain future.

This abandoned Civil War fortress is slowly being swallowed by the waters of Lake Borgne.

The crumbling ruins of this southern American fort have survived storms, war, and cults.

The third version of this tall sailing ship sits, rusted and burnt, in Lake Ontario.

This castle-fortress is a living example of the transition from medieval defenses to modern fortifications.

While many places make the claim, the Library of Congress says this restaurant is the birthplace of the hamburger.

A one-of-a-kind collection of a unique medium.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

An abandoned stretch of highway, deteriorating next to the operational one.

Abandoned Air Force base that has fallen into disrepair.