Perhaps The Coolest Thing I Have Ever Seen!

I don't know if what I saw was an optical illusion or, what it really is. But, since I traveled for Christmas this year, I had to fly. I had a window seat and when I looked outside, I saw a rainbow in the clouds. I have never been above a rainbow before but, what I saw was so awe inspiring. What we see from Earth is an arch and we all wonder where a rainbow begins and ends. What I saw from above the clouds and above a rainbow was a perfect circle with no ending or beginning. It was simply a beautiful, perfectly circular colorful ring! So cool that I struggle to put it into words. So, the question is, is a rainbow really and arch with a beginning and an end or a circle that seems to surround us from above? Either way, Rainbows are nothing short of beautiful reminders that our world is colorful and mysterious!