Halo, nimbus, icebow... what ever you call it, this natural occurrence is really pretty, especially if it shows up while you're visiting a beautiful place.
This optical phenomenon is produced when ice crystals create arcs, often around the sun or moon. The ice halo is similar to a rainbow, but rather than being composed of water droplets, it's made up of ice.
Check out photos of halos occurring around the world!
Marin County, California
Arches National Park, Utah