Mokolea Lava Pools

Steel rings embedded in rock enable hikers to ascend a picturesque slot canyon in the Mojave Preserve.

Islands of granite rise above the rainforest canopy to form unique microbiomes in a remote French territory.

This was the first ever National Lakeshore, established in 1966.

Two unremarkable-looking rocks on a cobblestone street are actually ancient wanderers; one a 150-million-year-old limestone, the other a 1.8-billion-year-old granite.

The Great Tsingy has a smaller, rose-colored cousin.

A hidden canyon deep in the woods of Indiana offers visitors a spectacular experience in nature.

Abandoned limestone quarry from the 19th century, now a man-made canyon reclaimed by nature.

This cave column thousands of feet below the earth’s surface is rightly named for one of the most colorful park rangers in history.