The Great Natural Bridge is a dozen-meter-high opening in the rock through which the Rak River flows. The river carved an opening into a 35-meter-high rock, with which the valley ends. The crab continues its journey on the surface for more than a hundred meters, after which it disappears underground. The bridge is a remnant of the former entrance to Škocjanska jama, the ceiling of which later collapsed. Technically, the Cancer stream beyond the Great Bridge does not flow on the surface, but through a cave without a ceiling.
The height of the river in Škocjan fluctuates greatly, which is clearly visible when we descend to the river bed. On the Great Natural Bridge, a metal plate marks the highest water level that was measured during the floods of 2000. At that time, the water reached the very ceiling of the bridge.