Site of James Cook's historic observations of the 1769 transit of Venus.

This community-driven organization uses education and eco-friendly technology to protect the environment.

One of Western Africa's oldest mosques, this Timbuktu icon has stood for nearly 700 years.

White llama terraces dazzle in Peru's "other Machu Picchu."

Enormous array of antennae fill a desert valley.

Stenciled handprints and wall paintings dating back 10,000 years, some of the earliest forms of cave art.

These layered sandstone mountains in China look like they are made of pressed crayons.

This awesome Spanish castle is so fantastical it was actually used on Game of Thrones.

The largest stone moai on Rapa Nui.

Remarkably intact Roman stone fortifications have encircled this Spanish city for centuries.

Part bookstore, part café, and part forest.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

Superstitious? Discover the witchy side of Mexico through its largest esoteric market.

Something's watching you.

The ruins of a lighthouse on the island Amelia Earhart never reached.

French scientists make up the majority of the few humans to occupy this remote island in the extreme southern Indian Ocean.

Tour the sci-fi-esque reality of governmental disease management.

Crumbling remnant of Rio's colonial past tucked behind Corcovado mountain in the neighborhood of Cosme Velho.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

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

Right up until the 20th century this network of man-made caves was the biggest village in Eastern Armenia.

The remains of an encyclopedic sculpture garden later used as an internment camp.

Over 4,700 miles of trees being planted to hold back the desert.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.