The Olwolgin cave, located 1400 miles from Melbourne, is a challenging dive site for experienced scuba divers. Getting to the cave requires a trek from a campsite about a mile away, where divers must transport heavy gear. The cave features a mix of salt and freshwater, creating a unique blurry effect in the water. Inside, divers can explore a complex network of tunnels, with a fascinating mixture of water salinity that affects visibility. Qualified divers can book trips through the Western Australia Department of Lands.