A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

The most visited, and possibly most controversial, museum in Germany.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Famously misunderstood wonder of the ancient world

The only rotating bar in New Orleans has been slowly spinning since 1949.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Home to items never before seen by the public.

A beautiful geyser under environmental threat.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

Elevated freight railway turned wildly successful urban park.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

The hallucinogenic center of the ancient world.

Monasteries on rock pillars, once accessible only by frayed ropes.

A nightmare for the claustrophobic lies hidden in Southeast Asia.

Thailand's distressed elephants find peace at this Chiang Mai sanctuary.

The most famous location in China was home to whole dynasties worth of imperial rulers.

A marvel of Byzantine engineering under the streets of Istanbul.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.