On approach to San Francisco International Airport, Amy Faulkner (Member 43,192) looked out of her window and was puzzled to see what looked like a rainbow tipped on its end.

Though we tend to think of a rainbow as an arch, if we’re high enough as we look at sunlight shining onto a curtain of rain that covers enough of the sky, a rainbow actually makes a full circle. It should really be a raincircle. Normally, however, from down at ground level, the Earth’s surface blocks at least half the view.

‘A child in the seat behind me also saw it,’ said Amy, ‘but everyone else had their window shades closed. It felt like private rainbow for us cloud watchers, welcoming us home.’