This picturesque horseshoe weir was first built in the 1600s to prevent flooding in the town of Bath.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

A quarter mile off the coastal tip of Maine you'll find the "Beloved Island" of Franklin Delano Roosevelt.

Twice a day, the water of the Petitcodiac River flows upstream in a surfable wave.

A mysterious spot where the laws of gravity seem not to apply.

These powerful, if squat, Canadian waterfalls flow in different directions depending on the time of day.

Iconic rock formations that allow for exploration during high or low tide.

The largest tidal whirlpool in the Western Hemisphere.

The Pentagon sits on a former island that was in Virginia at low tide and D.C. at high tide.

America's first federal monument.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The famous abolitionist’s preserved estate is one of Washington's finest monuments to its great Black citizens.

A derelict bit of transportation infrastructure hidden in the woods.

According to the experts at the Guinness World's Record office, this is the longest candy counter in the world.

A desert that rolls right up to the ocean, where it's so dry animals live off the fog.

A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

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

The 80-foot tire that looms over Michigan's I-94 was once a Ferris wheel in the New York World Fair.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

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.

An underground city of salt.

A misnamed well, with a deep dark past.

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