Einstein rings, such as the one that encircles galaxy NGC 6505, located near the center of the image, are examples of strong gravitational lensing, which occurs when light from a distant source is bent by a massive foreground object. For more on the ways astronomers learned how to identify gravitational lenses, turn to the article by Sebastian Fernandez-Mulligan on page 30 . (Image from ESA/Euclid/Euclid Consortium/NASA; processing by J.-C. Cuillandre, G. Anselmi, T. Li.)