This replica of the Greek structure is in the heart of Nashville.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

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

These azure waters were thought to lead to the Mayan Underworld.

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

These enduring murals depicting a distinctly Marxist tribute to capitalism could not even be defeated by McCarthyism.

Berry Gordy Jr.'s old home was the original headquarters of Motown Record Corporation.

The only surviving prototype for Buckminster Fuller's house of the future.

Lovingly nick-named the "Brick Dick" this municipal tower was winner of the World's Most Phallic Building Contest.

These grassy undulations on a stretch of University of Michigan campus aren't bad landscaping, they're art.

The city is full of whimsical portals to another world.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

The fifth-longest suspension bridge the world, connecting one Michigan peninsula to another.

Strange physical sensations and optical contradictions keep visitors coming back for more.

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

Former self-sufficient mental institution now a planned community.