People escaping slavery may have hidden inside a corpse vault.

The most decorated dog of World War I is preserved in the Smithsonian.

Home to items never before seen by the public.

The highest point in Washington state is a volcano covered in glaciers.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

World's first "penitentiary," meant to be humane, drove men insane.

Go inside to really appreciate this 500-year-old technological masterpiece.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

Romania's triumphal arch looks out over Bucharest.

The European towns of Brașov and Râșnov each have proud signs reminiscent of the Hollywood sign.