A startling, centuries-old subterranean marvel hides in plain sight.

This peaceful Sikh gurudwara serves around 50,000 free meals every day within its gilded walls.

Modest by day, illuminated majestically at sunset.

The world's second-largest sundial, made entirely out of stone.

Once an indicator of social class, the color blue has come to define this city on the edge of the Thar Desert.

More than half of this Indian palace is drowned but it looks all the more spectacular for it.

The 953 windows undoubtedly make this the world's most beautiful screened porch.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

An eccentric German artist built this weird and wondrous castle packed with shocking sculptures and alien art.

The final resting place of Christopher Columbus - or possibly someone else.

Built in 1512, the oldest cathedral in the Americas.

The first official clock in North America, it kept time for the Spanish government of Santo Domingo.

After Christopher Columbus died, his son built a fancy house to rule from.

The first hospital in the New World.

Columbus' failed colony in the New World.

The unusual patterns in this rock formation result from two distinct modes of weathering.

Erosion and various mineral deposits give this striking canyon its distinct color and soft appearance.

A tunnel with windows, so you don't miss out on the impressive views.

The fifth-longest natural arch in the world, and the longest outside China.

This quiet park's strange sedimentary spires were named after Kodak's color film.

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

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

This outsider art paradise is filled with dinosaur sculptures crafted from recycled machinery.