With its abundance of distant mountains across bodies of water, Alaska, on the right day, is a prime place to get a look at this mirage that has historically caused people to think they’ve seen castles in the sky or ships that disappear below the horizon. When the light is refracted multiple times, the illusion becomes increasingly intricate, hence the appearance of things like castles and mysterious buildings.

It all depends on the weather, but there are many places in the state to view Fata Morgana if the conditions are right. From the offices of the University of Alaska Fairbanks, the Alaska Range is subject to this illusion on certain days. From Anchorage across the inlet, if the Alaska Range looks a little odd and the mountains appear to be stacked columns instead of the usual craggy peaks, it’s likely Fata Morgana too. In Barrow, images over the frigid Arctic Ocean can be warped as well.

Here’s an interesting example of Fata Morgana, taken in Alaska a few winters ago. The mountains seem to look like distant skyscrapers, as if part of a frozen metropolis in the distance. Another image from Alaska shows a different view of this phenomenon, where the top of the mountain almost resembles a cloud of smoke. Even Mount Denali, the Great One, isn’t immune to its appearance being changed simply by temperature and light.

Next time you’re in Alaska, keep an eye out for mountains that might not appear exactly as they are, and impress your friends with your newfound knowledge of what happens during a temperature inversion.