One of the most extreme deserts in the world, these snow-free valleys harbor life, despite the hostile environment.

An approximately 500 million-year-old rock outcropping covered in fossilized bacteria.

This canyon is named for a unique geologic formation where the river vanishes underground near the mouth of the canyon and reappears farther down.

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

A giant light 13 feet high shines near Thomas Edison's old Menlo Park lab.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

This valley of hot springs and boiling mud pots is home to the record-holding "Geysir," which originated the English word.

The oldest (maybe) swimming pool in Iceland is a stunning oasis built into the side of a lush hill.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

This wrecked airplane has been sitting on a black sand beach since the 1970s.

Three columns of volcanic rock shoot out of the ocean.

The 7,000-year-old calcium carbonate formation creates a magnificent natural bridge.

A natural dome made of volcanic glass in Inyo National Forest.

More than 2,000 species of tropical plants call this nature preserve and sanctuary home.

This rock formation named for its unique shape is one of many that call the Alabama Hills home.

Erosion and various mineral deposits give this striking canyon its distinct color and soft appearance.

Across Ring Mountain is a vast collection of Native American petroglyphs unique to the region.

An off-the-beaten path cave with an underground lake.

This giant rock arrived at this quiet park thousands of years ago on the back of a massive glacier.

Perhaps the most spectacular grotto along the Algarve coastline.

Colorful sand dunes create a unique attraction in this part of Utah's red-rock country.

This conservation area is also home to many of the region's desert tortoises.

This massive sycamore tree has been labeled as one of the largest in the state.

Ten acres of the Kula Forest Reserve make up this wonderous state park.