It turns out the recognisable half-circle arch of a rainbow is a complete lie. When you're standing on the ground looking up at a rainbow in the sky, the curvature of the Earth usually blocks its bottom half. But when viewed from a higher vantage point, like from a plane, or the top of a crane, rainbows are magically revealed to be a complete circle.
This video was captured by a crane operator working on the 1,500+ foot tall Lakhta Center skyscraper in St Petersburg, Russia. From the machine's cab they were able to film the entire circumference of the phenomenon, which ends up looking more like a gateway to another universe, than sunlight simply being reflected from inside rain drops.