The only international border marker within the United States.

Ruins of a once-opulent grand Victorian resort.

A spring-fed pool so deep it's used for scuba diving as well as swimming.

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

There is an unmarked red button hidden over Houston's Buffalo Bayou that is just begging to pushed...

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

A Prada store in the West Texas desert that is never open for business.

A 90-year-old underground water reservoir offers a more industrial kind of tranquility.

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

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

Mysterious glowing orbs float through the desert night.

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

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

A small island hides in plain sight on Austin's Lady Bird Lake.

Free public park and gardens filled with peacocks and peahens.

Now abandoned, this East Austin school for the disabled began as the "State Colony for the Feeble-minded."

Some islands... they come, they go, especially on Lake Travis.

Circus cemetery for all the “showmen under God’s big top.”

This historic Civil War church has survived over a century of racial turmoil but still stands as a reminder of the town's roots.

This underwater old Texas hill town only resurfaces during harsh drought.

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

This one-woman cemetery was a small civil rights victory.

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

Crumbling hotel echoes with the sounds of the '30s.