I was browsing the web and I came across this webpage. It is a giant erosion simulator that models rivers and lakes. It is a very complex computer model of erosion and water flow that runs in just a web browser. The video above shows a demo of what it looks like. You can try the interactive simulation on your own computer at home by clicking on the link below. It is not just a video, it is a interactive simulation. You can change the landscape by moving your mouse and pressing the spacebar to add or subtract soil from the simulation. There are instructions at the bottom of the screen if you get stuck.
You can try it out here:
I recommend that you use the Google Chrome web browser.
It will not work in Safari because it does not support WebGL.
Or look at the webpage for it here:
This simulation sucks your computer's whole GPU, so it may run very slowly. Even our Mac Pro could barely handle it!