An 18th-century Spanish watchtower made entirely of seashell and concrete.

A tribute to Ponce de Leon's supposed quest for eternal youth.

The first bridge observation tower in the U.S. offers one of the best views of Maine.

This candy-striped tower is the farthest east you can go in the United States.

This 19th century granite fortification is one of the most well preserved forts in New England.

This tiny patch of arid sand sits in one of the greenest states in the United States.

The largest island on the great salt lake is home to curious creatures and strange stories.

The fifth-longest natural arch in the world, and the longest outside China.

The location along the shores of the Great Salt Lake of what was once called, "The Coney Island of the West", now sits barren due to arson and time.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

A miraculous natural phenomenon known as "the spring that breathes."

An architect's childhood fantasy treehouse made real.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

One man's ambition created this psychedelic log home.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

Remembering the Alamo with a full-scale replica of the 1836 city.

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

Some of the best pastries in "the Czech heritage capital of Texas" come from a gas station off I-35.

Austin’s local mountain isn’t really a mountain at all.

This theatre was made famous after Lee Harvey Oswald was captured inside watching a film.

Home to an endangered salamander, a full moon celebration, and a large spring-fed outdoor swimming pool.

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