A floating cat sanctuary on an Amsterdam canal.

Charnel house at the foot of Mount Sinai.

This otherwise unremarkable ski town building marks the site of Butch Cassidy's first robbery.

A small store filled with animal skulls and other curiosities.

A recreation of an Old West apothecary full of curios.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

A bizarre house filled with an astounding array of collections.

This titanic oil company sign is a reminder of the Americana boom of the 1970s and also its commoditization.

A kitschy, creepy St. Louis mainstay.

This is not your typical jungle gym.

This colorful gate stands as an entrance to the walled city of Old San Juan.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

The world's second largest single-dish radio telescope, once used to contact E.T.

The world's largest floating loon bobs in the lake to kick off an annual festival.

Minnesota's oldest and deepest mine is now an underground physics laboratory.

These crudely shaped folk giants may be the the second most photographed statues in the U.S.

17,400 lbs., 12 feet in diameter, and 29 years in the making.

This massive roadside mascot was the first version of the giant to illustrate his butt.

A towering tribute to decisiveness stands on the spot where Brigham Young and his followers decided that this must be the place.

The largest wildlife crossing in Utah allows local fauna to safely traverse the six-lane Interstate 80 at Parleys Canyon.

Pyramid home to an obscure religious group that practices modern mummification.

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

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.