A house of bones — but nobody is quite sure to whom they belong.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

An Austrian house of bones filled with hundreds of intricately painted skulls.

Mexico's astounding mummy museum with "the world's smallest mummy."

Mummified monks and the accidentally interred, in a 17th-century crypt.

Structure built from the skulls of vanquished foes.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Thousands of well-dressed mummies below a monastery.

The bizarre rocks of Đavolja Varoš are the result of natural erosion.

Northern Ireland's Brobdingnagian stepping stones.

A geological oddity topped with a 2,000-year-old pagan temple.

A seemingly endless landscape of pure salt stretches far across Bolivia.

The tallest stationary dunes on Earth also happen to sing.

Death road of Bolivia.

Popular tourist destination where witches in dark hats sell dried llama fetuses for good luck.

A valley of unique erosion patterns lends to a view like nothing on Earth.

Astronomical observatory above Lake Titicaca.

Nazca pilgrimage site covering 370 acres is a popular stop for archeologists and looters.

Extraordinary rock formations in open Peruvian fields.

Surreal riveted sea forts once protected the Kent shores from German attack.

A Turkish ghost town abandoned in a population exchange with Greece.

In a long-dry lake bed, these groups of massive stone pillars bear a striking resemblance to clumps of everyone's favorite fungi.

A naturally beautiful, seemingly bottomless deep blue spring.