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

The artist James Turrell is repurposing an extinct volcano crater as an observatory to experience the cosmos.

Thousands of Mexican Free-Tailed Bats soar around an abandoned storm drain at sunset each summer.

Originally conceived as part of a proposed Arizona State Capitol building in the 1950s, this structure built in 2004 stands as a monument to the architect's legacy.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.