The ruins of a pre-Columbian fortress city so secure it held off the Spanish conquistadors for over 20 years.

You can swim in these highly salty, mesmerizingly blue lakes in the Atacama Desert.

The largest geyser field in the southern hemisphere is a spectacular sight.

A newspaper editor turned this abandoned island into a tortoise nature preserve that's now the world's smallest national park.

Réunion Island's highest point is a 2 million-year-old volcano and a paraglider's paradise.

A volcanic crater that visitors can look inside.

This was once the center of the Birdman cult, and is now a World Heritage Site.

The largest stone moai on Rapa Nui.

Cooled, fractured lava formed this geometric rock feature.

Three-story concrete ram with a permanent gift shop.

Critics argue this boab tree has been mislabeled for the sake of dark tourism, undermining its spiritual significance.

The abandoned remains of a once popular zoo, and the grave of the last known Tasmanian Tiger.

Victoria's largest salt lake is a favorite haunt for photographers and stargazers.

These sea cliffs are an epic natural wonder.

The bones of this aquatic dinosaur turned to opal over the centuries and the beast's remains were almost sold as jewelry.

These Australian rock formations look like Martian beehives that have grown up out of the landscape.

Clusters of huge boulders in the Australian Outback.

White cockroaches and other cave species occupy this massive series of lava tubes.

The red crab exhibits one of the most spectacular migrations on earth, despite manmade obstacles.

Putt your way around Australia in a black light environment.

Living fossils in this remote Australian bay provide a glimpse of what Earth may have looked like 3.5 billion years ago.

This Australian beach is composed of tiny shells.

A stray meteor left this picturesque hole in the Australian outback.

Alien rock formations grown from the sands of an Australian national park.