A view across Saturn's ring plane, looking towards the so-called ring mountains. The ring mountains are strange vertical structures found on the edge of Saturn's B ring. They are not solid, but are rather a constantly changing accumulation of ring particles thrown out of the normal ring plane by the gravity of moonlets orbiting within the rings. Some of them are as much as 2.5 km in height - in stark contrast to the average thickness of the rings, which is a mere 10 metres.