Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

The largest cave shaft in the world is home to thousands of birds and popular with BASE jumpers.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Olfactory delights in San Francisco's Botanical Gardens.

The legendary building that needed ghostly approval before being built.

Microscopic fossils suggest Australia may be the birthplace of sulphur-based life forms.

Sacred waters rescued from the wrath of a volcano.

Recently restored menagerie of Victorian-era beasts.

"The most colorful grottoes of the world.

The location of the last stand of Charles Manson's doomsday cult.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Take a drunken tour inside the world's largest known geode.

A picture-perfect town, perfect for blowing up.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

Rare signs of the former Soviet Union in the Caribbean, though not where you'd expect them.

Aqua white sand highlighted with fiery red rocks.

Machismo turned on its head: the lady's hand goes to the dude with the bigger brain.

A naturally beautiful, seemingly bottomless deep blue spring.

This landlocked lake is the world's largest on an island.

A whimsical bridge adorned with decorative dragons.

A petite castle folly in the English countryside.

A giant pineapple, a symbol of hospitality, and an amazing vacation rental option.

A modern English garden of eccentric beasts, follies, and oddities.

16,500-acre ranch filled with American heritage, geological wonders, and a giant pile of tires is the crown jewel of an intriguing tug-of-war.