A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

A fiery-red region of scooped out land still largely untouched by civilization, tourists or otherwise.

The most elaborate of 12 medieval arched doorways to the old city of Burgos.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

A historic Christian shrine nestled within a spectacular natural cave.

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

A towering monument in Spain has proven to be more labor-intensive than initially planned.

Cliffside houses provide a spectacular view from their perch above the valley.

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

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

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

The glowing blue Nymphaeum of Emperor Tiberius.

The stunning interior of this Gothic church is covered in ornate gold details.

Elaborate tile work in this railway station tells the story of Portugal.

The world's most elegant power lines.

A 16th-century Andalusian palace.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

Remarkably intact Roman stone fortifications have encircled this Spanish city for centuries.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

One of the world's oldest universities houses an incredible collection of anatomical models, mummified body parts, and human bones.

Seaside ruins of a settlement that date back to the first century B.C.

Thanks to an acoustic anomaly, this unassuming stone bench has heard one hundred years of secrets.

Giant granite sculptures representing family on the northern coast of Spain.