An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

The discovery site of the "Capitalsaurus," the official dinosaur of Washington, D.C.

There’s a hidden military meme engraved on the World War II Memorial.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

This tin chapel was built by POW's during World War II and is painted to look like something much more grand.

The discovery of this Neolithic settlement, which contained a Stone Age "cathedral," threw archaeologists for a loop.

Thanks to both terrific preservation and historic vandalism this ancient site is known as the "Heart of Neolithic Orkney."

Enter the world under the hill at this ancient UK burial chamber.

This tiny island featuring 9th-century Viking ruins is only accessible at low tide.

Possibly the oldest of Britain's ancient henges is also one of its most stark.

A red sandstone freestanding monolith rises out of the sea in northern Scotland.

The true age of this ancient stone circle is unknown, but its stunning vista isn't in question.

This Scottish burial tomb once held hundreds of ancient eagle bones.

Twice a year, this Orkney town hosts a rowdy game of medieval mob football.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

A line of blue paint marks the route of the inaugural parade.

The first memorial dedicated solely to the Black troops who fought for the Union.

A display of magnificent stained glass windows is the first exhibit of its kind.

A source of civic pride, though the reason for its construction is unknown.