The attic of a four-century-old canal house hides a clandestine church.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

This unattributed sculpture in Amsterdam is hiding in plain sight.

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

Craggy concrete faces are hidden in the walls of this artificial cave along the San Antonio River.

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

This small stone building, the final work of a renowned artist, offers a peaceful environment with radiant, colorful glass windows .

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

This simple frog painting created by musician Daniel Johnston embodies the spirit of Austin.

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

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

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

An abandoned, decaying sculpture garden built by an eccentric physician in the 1920s now looks more like a forgotten cemetery.

The 40-foot-tall votive candle is the largest of its kind.

This hidden sculpture garden full of Wild West art is one of San Antonio's best-kept secrets.

Legend has it the commander of the defenders drew a fateful line in the dirt with his sword just before the final battle.

A 131-year-old wunderkammer of Texas history.

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

Fifty years after a “blast blasted blubber beyond all believable bounds,” this idyllic natural area commemorates the carnage.

The park preserves a single, rare species of carnivorous plant that spells doom for unsuspecting insects.

Only known mainland rookery of the threatened Stellar sea lion.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

The largest wooden building in the world now houses a fascinating collection of aircraft.

This unassuming cheese empire in rural Oregon churns out more than 150,000 pounds of cheese each day.