This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

The largest stone moai on Rapa Nui.

Fire meets ice at the southernmost volcano on Earth.

Nimrod Polar Expedition base, and home to hundred-year-old frozen whisky.

These passages carved from the Antarctic ice hold strange shrines to the harsh southernmost climes.

Commemoration of a sea voyage gone mysteriously wrong.

The highest tides in the world come in and out here twice a day, allowing you to essentially walk along the ocean floor.

Iconic rock formations that allow for exploration during high or low tide.

A school teacher's massive and terrifying self-built castle.

Final resting place of Antarctic explorer Ernest Shackleton.

In the northernmost city in the world, it's illegal to be buried because it’s too cold for bodies to decompose.

Cold storage for agricultural biodiversity.

This abandoned mining village was predicted to resist decay longer than any other modern human settlement.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

Most-visited and most-photographed slot canyon in the American Southwest.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

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

A one-of-a-kind sundial at the Very Large Array honors a radio astronomy pioneer, incorporating the original piers from his breakthrough radio telescope.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

Dramatic river bend surrounds a natural red-rocked pedestal.

A reproduction of earth's many biomes.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.