July 2, 2026, 2:27 pm | Read time: 3 minutes
In the midst of the Paraná Delta in Argentina, there floats an island surrounded by various conspiracy theories. Some suspect it to be a UFO, others the home of a deity. The reason: its nearly perfect circular shape and the fact that it moves within this circle.
About 70 kilometers from Argentina’s capital, Buenos Aires, lies a water-rich swampy landscape. The delta of the Paraná River stretches over approximately 230 kilometers here. Several islands and a labyrinthine network of streams and wooded wetlands create an extraordinary landscape.
The Discovery of the Circular Island
Also extraordinary is a small island that was first discovered in 2016 on aerial images on the internet. As reported by “BBC Wildlife,” it was later determined that the sensation had been visible on maps since 2003–it just hadn’t been noticed before.
This is hardly surprising: The vast delta is still largely unexplored. Argentine filmmaker Sergio Neuspiller stumbled upon the nearly perfect circle in the lush green delta somewhat by chance while scouting the region for a filming location using Google Earth.
As reported by “El Observador,” the film crew subsequently flew over the landscape in a small plane to determine the exact coordinates of the island. Later, they reached the site on foot. “We found the perfect circle, just as it appears from the air. The water looked black but was actually completely transparent–something almost impossible to find in the delta. The reason was the black substrate,” said the director.
From the air, the island resembles a green pupil in a black eye. That’s why Neuspiller named his discovery “El Ojo”–the Eye. On Google Maps, the location is still marked with the addition “Misterioso.”
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How the Phenomenon Can Be Explained
As mysterious as it seems at first glance, researchers have since found a plausible explanation for why both the island and the surrounding basin look so perfectly–almost man-made.
Various aerial images show that the approximately 120-meter-wide vegetation area moves within its circular basin. Sometimes it touches the left edge, sometimes the right.
Apparently, the island consists mainly of lightweight organic material such as matted grass and decomposed plant remains. This allows it to float on the water’s surface. Currents beneath the island cause it to slowly rotate on its axis. When it touches the edge of its basin, the edges of the island and the shore rub against each other over time. This gradually grinds both into an almost perfect circle. This process continues to this day–the island is likely to become smaller over time.
Can You Visit “the Eye”?
As the elaborate expedition of the film crew shows, reaching this natural spectacle is anything but easy. The swampy landscape is difficult to traverse. Off the established tourist paths, you need at least a local guide–and depending on the route, probably a boat as well. The best view of the extraordinary circular shape is from the air.
A visit to the Paraná Delta is still worthwhile, especially for nature lovers and hiking enthusiasts. The unique landscape provides a habitat for numerous plant and animal species. In addition to willows and extensive fields of water lilies, the Ceibo, Argentina’s flowering national tree, also grows here. Moreover, the delta is one of the country’s most popular regions for bird watching.