Search #weddingcakerock on Instagram and you'll come up with more than 3500 images of grinning young people on and around a curiously geometric, starkly white clifftop overlooking the ocean.

Some are standing, a few daredevils are performing handstands or leaping in the air but the vast majority are seated on the chiselled cliff edge, legs dangling 80 metres above the roiling ocean below.

If performing a handstand on Wedding Cake Rock in Royal National Park looks dangerous, that's because it is. Credit:Instagram

If it looks dangerous that's because it is. Outrageously dangerous. One person has already died at the location and there are fears more could follow.

Wedding Cake Rock is on the Coast Track in the Royal National Park, about two kilometres south of the village of Bundeena. The track is popular during the summer months and during the annual whale migration but it's generally the sole domain of just a few hardy walking types and trail runners.