Often you can see a second rainbow above a brighter one.
This is caused by extra reflection inside the raindrops.
Since the secondary rainbow is formed from two reflections instead of one, it has a wider radius than the first rainbow and its colors are reversed.
The red is on the bottom and indigo on the top of the second rainow.
The secondary rainbow also isn't as bright as the first because it's a secondary reflection.
A third or a fourth rainbow also can occur because light can be reflected more than two times within a raindrop.
But we rarely see them because they are even fainter than a secondary rainbow.