Meant to be one of the most extravagant hotels in the world, now an eerie, abandoned architectural gem in Mexico City.

Explore the atmospheric ruins of an abandoned convent in the dense forests of Mexico's first national park.

Extraordinary sculpture garden created by an eccentric English poet.

Every equinox this Maya pyramid puts on a spooky ancient light show.

The famous artist couple lived and worked here, in two different houses separated by a bridge.

An Aztec snake god has taken the material form of an apartment complex.

These azure waters were thought to lead to the Mayan Underworld.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Part bookstore, part café, and part forest.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

The ruins of a 16th-century bridge loom over Olivença's sovereignty.

Before this rocky hill was home to a chapel, it was used as a lookout by Romans and Moors.

Legend has it the lovelorn tears of a princess and a shepherd boy formed the blue and green twin lakes in the Azores archipelago.

An abandoned anti-smuggling station decays along the boundary between Portugal and Spain.

An icon of the city, this chapel features an amazing dome ceiling and offers panoramic views.

An abandoned mining complex in Serra do Gerês.

This Portuguese bullring is built right into the caldera of an island volcano.

This abandoned fortress still stands guard over the Guadiana River despite a history of warfare.

One of few vertical lava tubes in the world accessible by foot.

A naturally occurring amphitheater carved by erosion into the mountainside.

A small sanctuary carved into the mountainside near the tallest point in continental Portugal.

This enigmatic Roman tower lurks just outside Belmonte.

The crumbling ruins of an abandoned 12th-century monastery.