Iguazú waterfalls, Argentina. One can see numerous rainbows through the water drops when the sun has a good inclination. Here is the shot of a primary rainbow at the very start of one of the falls of the "Devil throat". The secondary rainbow is visible, with the colours inverted.
Benlet26
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>