This unusual three-way wooden foot bridge spans two rivers at once.

A unique walk through hundreds of cactus plants, including some that stretch over 8 feet tall.

A spring water stream jumps through a walkable "bridge" cavern and a narrow canyon.

Ancient rock-hewn town that witnessed key events of Georgian history.

Ruins of a Carnegie family mansion on Cumberland Island.

This former mining town was named the most toxic town in America.

Ghost town with a beer-drinking goat for mayor.

A fortified city, home to a remaining population of five families

Macbeth's infamous "Great Birnam Wood."

Behind this beachfront shop lies a spectacular, colorful sea cave with an equally colorful past.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

A cave's rare beauty held a cavernous secret hidden underground.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

The land is home to swimming ponies and a legendary 18th-century treasure.

Sitting atop a rock on Michamvi Pingwe beach, this restaurant becomes its own island at high tide.

This “living museum” at UCLA exhibits thousands of plant species from all over the world.

A 16th-century monastery boasts a lush array of plants native to Mexico’s most biodiverse region.

A peaceful, unique botanical garden complete with waterfalls, mini islands, and swans.

One Portuguese poet described this cape, the westernmost point in mainland Europe, as "where the land ends and the sea begins."

An abandoned mining complex in Serra do Gerês.

A cluster of granite granaries perched on stilts.