Abandoned railroad tunnel is home to a colony of three million Mexican free-tail bats.

A Texas cave network is home to some of the world's most spectacular-looking and bizarrely named mineral formations.

A private collection of massive steel monsters guarding a Texas pipe works.

The summer home of the largest colony of bats in the world.

Tracks near this Texas nature site were once thought to support the Creationist belief that man and dino coexisted.

The world's largest squirrel statue clutches a pecan bigger than your head.

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

Visitors can walk over the largest concentration of Columbian mammoths to have died from one event.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

A recreated Stonehenge stands in a country field, complete with Easter Island moai heads standing as sentries.

Mysterious glowing orbs float through the desert night.

A 24-hour vending machine restocked daily with homemade full-sized pecan pies.

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

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

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

A popular swimming hole that hides one of America's most deadly diving spots.

An emerald-green grotto just a short trip from Austin.

The famous 102-year-old circus elephant was struck and killed by lightning.

Touch an actual dinosaur bone at this eclectic trove of Rocky Mountain treasures.

A collection of huge, site-specific sculptures sitting in the Montana woods.

For thousands of years, Native American hunters drove buffalo straight off this cliff in Montana's Yellowstone Country.

The oldest badlands in North America, Makoshika State Park takes it name from the Lakota words for broken land.

A small Montana town commemorates the dog who waited at the train station every day for his owner to return.