Mesmerizing full circle rainbow on the Stairway to Heaven in Hawaii
Mesmerizing full circle rainbow on the Stairway to Heaven in Hawaii

This full-circle rainbow is called glory, and it is an optical phenomenon resembling an iconic saint's halo around the shadow of the observer's head, caused by sunlight or (more rarely) moonlight interacting with the tiny water droplets; that comprise mist or clouds!

Fascinating!