Marble Runs.

The Ravensburger Gravitrax Starter Set is a must-have STEM toy for any budding scientist, engineer or inventor. This exciting and award-winning interactive track system lets you build and experiment with gravity, magnetism and kinetics while creating an amazing marble run. With the included pieces, you can create your own custom tracks and obstacles to challenge yourself or compete against friends. The possibilities are endless! The set also comes with multiple accessories for increasing the difficulty of your tracks and adding fun elements like loops, jumps, and targets. Read on to find out more about this versatile set!