I Spy, From Space

Richat Structure (Eye of the Sahara)

From orbit, a 40 km bull's-eye of concentric rings stares straight up out of an otherwise featureless stretch of the Sahara. NASA's Gemini IV astronauts photographed it in 1965, and it has been a landmark for crews in space ever since. For years it was assumed to be an impact crater, which is a very reasonable guess when the desert appears to have a target painted on it.

It isn't one. Geologists now describe it as a deeply eroded dome, pushed up roughly 100 million years ago by molten rock rising underneath. Wind and water then stripped it down until only the hard quartzite ridges were left standing in rings. In the satellite view, look for the red and gray target rings, and for the sand of the Erg Ouarane creeping in along the south side like it has been trying to fill the thing in for a very long time.

What on Earth? S01E03 "Secrets of the Sahara" (2015)

Science Channel's satellite-mystery series put the Eye of the Sahara front and center in its third episode, walking through why a 25-mile structure spotted from space in 1965 took so long to explain. The same episode also chased strange cloud formations over an island in the Indian Ocean, which gives you a fair sense of the show's tone.

Nazca Lines: The Hummingbird

A 96-meter hummingbird is scratched into the floor of the Nazca Desert. The Nazca people made it sometime between 200 BC and AD 500 by clearing away the dark surface stones to expose the paler ground underneath. From the ground, it looks like a few faint paths going nowhere in particular. From above, the whole bird snaps into focus: long beak, spread wings and a fanned tail, all drawn as one continuous line.

Ornithologists think it shows a hermit hummingbird, a species that lives in forests far to the north and east, not anywhere near this desert. Why the Nazca drew a bird they would have had to travel to see, at a size only visible from the sky, is the kind of question that keeps the Nazca Lines on every list of unexplained places. The satellite view is framed tight enough to see the tail feathers.

Darvaza Gas Crater (Door to Hell)

A glowing pit about 70 meters wide sits in the middle of the Karakum Desert, burning. The usual story traces it to a 1971 Soviet drilling accident, when engineers set the escaping gas alight and expected it to burn off in a few weeks. Some local geologists tell it differently: the ground collapsed in the 1960s, and the fire was lit in the 1980s. The records are missing or classified, so nobody can say for sure. It is a strange thing to be uncertain about, a hole that has been on fire for half a century.

From above, look for a neat ring of orange-lit rock with a worn sightseers' track around it. Catch it while you can. Turkmen officials said in 2025 that the fire had shrunk to about a third of its former size, so the Door to Hell may finally be closing.

Die Trying "Crater of Fire" (2014)

Explorer George Kourounis became the first person known to climb down into the crater, in an expedition sponsored by National Geographic. After two years of planning, he had roughly 17 minutes on the burning floor to take gas readings and collect soil samples before being hauled back out. The team wanted to know whether anything could live down there. (Bacteria, it turned out, could.)

Pripyat

Pripyat was founded in 1970 as a Soviet model city for the workers at the Chernobyl Nuclear Power Plant. By 1986 it held 49,360 people. On April 27, 1986, the day after Reactor No. 4 exploded, every one of them was put on a bus and told they would be back in a few days. They were not. The city has been empty ever since.

From above, Pripyat still looks planned. The neat grids of apartment blocks are all there, only now the forest has grown up between them and is slowly closing over the streets. Zoom in on the amusement park. The Ferris wheel was due to open for May Day 1986, five days after the evacuation, and it never officially carried a single rider.

Mysteries of the Abandoned "Chernobyl's Deadly Secrets" (2017)

Science Channel followed engineer Philip Grossman, who had been into the Exclusion Zone about ten times (and got married there in 2015), as he chased leads about what really caused the disaster, including talk of espionage and a Soviet cover-up. Grossman came away pointing more at a reactor design flaw than at human error.

Grand Prismatic Spring

From above, the largest hot spring in the United States looks like a giant glowing eye: a deep blue pupil ringed by green, yellow, orange and red. It is about 110 meters across and around 50 meters deep, and the water coming out of it runs near 160°F (70°C). The center is too hot for anything to live in, which is why it stays that impossible shade of blue.

The rainbow rings are alive. They are mats of heat-loving microbes, and their pigments shift with the water temperature and the season, so the eye changes color over the year. In the satellite view, look for the pale mineral flats around the edge and the rusty orange streaks running off the spring like something bled out of it.