A wild west land agreement was etched right onto this historic Idaho stone.

Natural rock water slides hidden in the remote forests of northern Idaho.

These black pillars of volcanic basalt seem to call mountain climbers with an unbreakable siren song.

Home to the deepest rift anywhere on Earth.

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

Rippling sand dunes frozen in the Arizona rock.

A preserved oasis with traditional Andalusian-style architecture and beautiful views of the Nile.

The deadliest diving spot in the world is also a stunning geological marvel.

Known as the Sistine Chapel of Egypt, this tomb houses some of the most well-preserved paintings in Egypt.

The once great capital of Egypt now crumbles forward as evocative ruins.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

The massive cave church of Cairo's Zabbaleen community is one of the largest Christian churches in the Middle East.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

An endless sea of white conical domes.

Ozymandias’ time-keeping temple.

An ancient instrument used to measure the waters of the Nile so Egyptian farmers would know whether to expect famine or flood.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

Italian cave with exceptional acoustics and an unsavory history.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

The glowing blue Nymphaeum of Emperor Tiberius.

Renaissance villa and gardens complete with a tormented colossus.

Geothermal waterfalls in Tuscany.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.