A couple camping on the shores of Lake Michigan recently captured images of a mirage of the Chicago skyline inverted over the water.

“We were definitely not expecting to photograph this,” stated Josh Super, who was at Warren Dunes State Park near Bridgman, Michigan, with his girlfriend. He said they were hiking at sunset when his girlfriend noticed the odd horizon.

“I had absolutely no clue what we were looking at,” said Super. “It appeared as though something foreign was rising out of the middle of Lake Michigan.”

Meteorologist Ellen Bacca explains that events such as this are rare, but when they do happen it is usually from mid-April to mid-May on calm, clear days or nights. This type of mirage with an upside down image is called a “superior mirage,” in which the image appears above the actual object.

Mirages are most likely to form when very warm air slides over land and the wind stays calm. The change in air density bends light waves and creates the mirage.

“I didn’t realize this phenomenon would turn out to be so rare and that most people were not aware of it,” said Super. “It was a really cool thing to learn about, and I’m just glad we were able to experience it.”

Source: WANE