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

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

A set of ancient drawings in the desert of Peru that are so massive, many of them can only be fully seen from the sky.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

Death rituals and sacrifice inside a Peruvian megalith.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

A museum marks and documents the site of the Titanic's launch.

Northern Ireland's Brobdingnagian stepping stones.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

The first declared National Monument in the United States.

The first tourist attraction to offer tours for interstellar tourists.

This trio of Australian rock spires may have inspired aboriginal legend or just modern tourism.

Come for the flowers, stay for the bats!

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

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

A mysterious castle built as a monument to lost love.

A bizarre roadside attraction and the first instance of miniature golf in the world.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

Enormous lake at the bottom of a unique cave system.

This high point in the Great Smoky Mountains is said to be home to the chief of all bears.

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

You can climb to the summit of Black Mountain, as long as you sign the waiver.

This boulder stays on its mountain thanks to a huge chain and on the map due to local legend.