Holes

The perfectly named cave drop is the deepest in the continental United States, almost matching the height of Seattle’s Space Needle.

A rugged lava field dotted with molds of the ancient pines that were growing when the volcano erupted.

A massive natural rock arch gives the Tuscan mountain its own window to the sky.

Folklore says this medieval fortress was plopped atop a portal to hell to trap the demons below.

A winding, blood-red tunnel of hardened lava navigable by foot.

These mysterious circular formations are actually remnants of 19th century gristmills.

This large maar crater in Oregon is the bigger brother to Hole in the Ground.

This geothermal hot spring hides beneath a slowly growing mineral dome.

This locally-famous crevasse in New York State is icy all year round.

The world is full of swimming holes, but few compare to Samoa’s idyllic To Sua ocean trench.

The most visited pilgrimage site in Armenia once held a saint in a pit for 13 years.

A clear blue swimming hole with hidden caves, still unexplored.

Mined to a depth of 240 meters with a perimeter of about 1.6 km, the largest hand-dug excavation in the world.

Tasked with beautifying a disused stretch of industrial land one artist filled a hole with grass.

The United States's largest hand-dug well is topped with a state-of-the-art museum.