Rain-sticks can be found in many different parts of the world. People from different cultures may have discovered how to turn a cacti or other similar plants into rain-sticks on their own. Some say the rainstick was used in ceremonies to call for rain.
This photo shows the Capado cactus from the southern part of Atacama Desert, the driest place on earth. This type of cactus lives about 60 years and when it dies, after it dries out, the cactus is hollowed out, creating a tube. The spines of the cactus are cut off and pushed inward so they protrude inside the hollow tube. The tube is then filled with small pebbles or beans and the ends blocked off. When the cactus tube is turned the pebbles fall inside, hitting the spines of the cactus creating the sound of rain.
Take a look at this video of a lady explaining the Rainstick and demonstrating how it is played. Stay with the video because it really sounds cool when she turns it on the side to play it.
I know you must be curious about what it looks like inside but please don’t cut it open. Here is a video of someone doing this so you won’t have to.