This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

Inside this Icelandic greenhouse, geothermal energy keeps tomatoes warm and growing.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

William Faulkner kept his beloved estate wild and untamed.

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

A Norwegian-born sculptor created these soaring guardian angels at the entrance to Hoover Dam.

A giant open-air sculpture made of over 200 full-sized boats.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

The highest point in Texas is capped by a big silver pyramid.

An abandoned quicksilver mining town surrounded by the Big Bend parks.

Foragers once flocked to this big beautiful bayou to hunt for pearls.

The biggest drug trafficking passage between Mexico and the U.S.

This hollowed salt dome is the largest oil storage facility in the world, hoarding 250 million barrels of crude oil.

This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

The tree is thought to be the oldest oak in Texas and was once crowned state champion for its monumental size.

Decades of discarded bottle caps line this alleyway, a fixture of Texas A&M.

Civil War dumping ground for the bodies of terrorized Union sympathizers.

A grove of colossal man-made flowers built to collect the sun's rays.

Controversially claiming the title of world's biggest bass drum, UT's Big Bertha was once made radioactive by the Manhattan Project.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

Locals dubbed it the "Owl Building" because of its bird-like appearance.

This unique structure in suburban Austin is made up entirely of other people's castaways, and constantly changing.

The upstairs reading room is packed with millions of rare books, literary manuscripts, and historical treasures.

One part antique store, one part curiosities hodge-podge.