Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

An eerie collection of the surviving structures from a past celebration of the future.

A 16th-century Andalusian palace.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

Vibrant street art created with mixed media.

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

A contemporary art installation housed within a Gothic cathedral.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.

Seemingly grown on some other world, these New Mexico rock formations look like a disused science fiction set.

Legends surround this jagged rock formation in the New Mexico desert.

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

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."

A Tucson museum and performance space full of found-object movable sculptures.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

David Sedaris called it "The greatest shop in the world."

This Tuscan lake hides a 13th century town that is still visible when the water recedes.

An amazing collection of wax anatomical models and terratological models.

An extraordinary collection of 18th century anatomical waxworks.

This zoological museum began as the first great curiosity cabinet.

The mummified relic of St. Catherine sits forever on a golden throne.

A diverse collection of wax, bone, papier-maché and mummified relics.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.