By Darren Orf
Publication Date: 2026-10-14 12:00:00
Here’s what you’ll learn when you read this story:
- Nature generally doesn’t form perfect circles in organic landscapes, but a strange island in the Paraná Delta in Argentina may be an exception to that rule.
- El Ojo, a 120-meter island of decomposing plant matter, is a near-perfect circle inside an equally round lake.
- First spotted on Google Maps in 2016, the formation resembles ice disks, which spin when river eddies create rotational shear—and scientists say the same forces are at work in this wetland 50 miles northwest of Buenos Aires.
When you spot perfect circles in isolated places from a bird’s eye view, whether from an airplane or while poking around on Google Maps, the formation is usually one of two things. The most common is central pivot irrigation, a farming technique designed for pipes on wheels to rotate like the hands of a clock around a central well, forming green cropland in otherwise untamed landscapes. The second, albeit more rare, explanation is crop…
