The subtle blue is a result of preferential scattering of short-wavelength light travels down the vertical shaft and hits the waterfall mist in the moonlight. The Natural Bridge is a naturally formed rock arch over Cave Creek, a tributary of the Nerang River. It was formed from a waterfall which undercut a cave beneath the waterfall and dug a pothole on top, until the two joined and the creek flowed through the cave, leaving an arch across the front. Springbrook National Park, Gold Coast Hinterland, Queensland. UNESCO World Heritage listed Gondwana Rainforests of Australia.