The interactive ball track system from Ravensburger.

With the GraviTrax® marble run system, you can build your own marble run world by creatively using the laws of gravity. Use the various building elements to create an action-packed course and use magnetism, kinetics, and gravity to get the marbles to the finish line

With the GraviTrax® marble track system, you can guess gravity in a playful way, and with various expansions, it can be enlarged for unlimited building and playing fun! Add even more speed with the expansion sets.