This lone tree and dramatic sandstone outcropping are so beloved by Michiganders they can be found on one of the state’s coins.

Legend says train robbers stashed their gold within the depths of this unusual cave.

The world's longest known cave system.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

This freshwater spring fills with 10,000 gallons of water per minute.

Bad farming practices caused this unnatural natural wonder.

Traversing these canyons, visitors can take in stunning views and glimpses of the region's history.

One of the largest trees of its kind in California.

Every equinox this Maya pyramid puts on a spooky ancient light show.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

An island graveyard with spectacular views of the Caribbean.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

Rare recess caves fill this unbelievably beautiful Ohio park.

A miniature world of concrete and stone in Springfield, Ohio.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."

A throwback train ride transports passengers through one of the lesser-known national parks in the country.

Faces carved into the cliffs create an otherworldly walking trail.

Ghost stories surrounded this “castle,” the only structure from a huge mansion that was never built.

Landmark dedicated to the plight of the American Indian in the 21st century.

The angel of death appears to weep black tears at this grave marker.

Funded by John D. Rockefeller, this is one of the earliest, and most beautiful, shopping arcades in America.

This spectacular public market has got meat, fish, vegetables, baked goods, and enough kielbasa for a lifetime.