When astronauts look at Earth from the International Space Station at night, they see twinkling lights pointing to cities, boats, and other man-made objects. But daytime shifts are a different story, so European Space Agency astronaut Samantha Cristoforetti was drawn to a strange spot she saw in the desert.

“Interesting sight! A bright spot in the Negev desert… It’s very unusual to see man-made things in daylight,” Cristoforetti tweeted on Thursday, sharing three photos showing a white dot over a brown landscape.

Cristoforetti said this image is of a Solar power plant used to generate renewable energy from the Sun. In this region, there is one of the tallest Solar power towers in the world. The tower of the Ashalim Solar thermal power station in the Negev desert is 250 meters high and large enough to be seen from the International Space Station. It reflects a lot of sunlight. Looking a little closer, it looks like this:

The solar station has about 50,000 mirrors that focus the Sun’s light on the central tower.