Buenos Aires' city of the dead contains some very famous remains, including Eva Perón.

The world's first aircraft factory has been hiding inside an automobile plant for almost 80 years.

There is beauty and history in the ruins of this former company town.

The entire length of the border is marked by a 20-foot-wide slash through the trees.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

The largest radio telescope in the world searches for extraterrestrial life from the remote limestone peaks of southern China.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

The Forest Service's surprisingly sophisticated collection of wildfire prevention art features America's most beloved bear.

This Italian dam is covered in salt-hungry goats who manage to scale its almost vertical face.

Hidden behind Lincoln's head is a 70-foot-long chamber containing enamel plates documenting American history, sealed in a teakwood box in a titanium vault.

A remote horde of architectural treasures fit for Indiana Jones.

A Cold War atomic camp buried under the ice is now emerging because of global warming.

The roadway bend where highway painters practice their craft looks like expressionist art.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

These red marks, seemingly placed at random, are in fact not.

The U.S. military dumped millions dollars worth of goods off a beach in Vanuatu, purely to spite the British and French.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

A treasure trove of pathological, forensic, parasitological, and anatomical specimens.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

A hard-to-reach oasis in a desolate corner of Death Valley National Park.