A massive underwater sinkhole made famous by Jacques Cousteau.

A wonderful collection of all things Oz is nestled in the heart of Kansas.

Underwater art project will double as a massive artificial coral reef to help regenerate the damaged ecosystem.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

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

A Texas-sized particle collider that was abandoned due to its Texas-sized budget.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

An emerald-green grotto just a short trip from Austin.

A gargantuan crystal kingdom.

A playground built by the kids that is a child's wonderland, and a helicopter parent's nightmare.

A Barbary Coast watering hole built into a Gold Rush shipwreck.

World's largest cave was only discovered in 1991, and now offers tours to the public.

A battle between nature and architecture in the Cambodian jungle.

Large Hadron Collider and the Birthplace of World Wide Web.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A beautiful and classically designed villa, with an hourly infestation of monsters.

Monasteries on rock pillars, once accessible only by frayed ropes.

Moss and stone turn this waterfall into an otherworldly liquid veil.

The hermits of Karoulia protect their asocial lifestyles by living on the vertical face of a treacherous precipice.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

An abandoned saucer-shaped monument in the Bulgarian mountains.

The spectacular history of spectacles on display.

Ship-sized kinetic sculptural fantasy.