Known as The Grotto, Fairy Grotto and in the past as Harpers Cave, this is an incredibly picturesque swimming hole and waterfall, inside a narrow slot canyon. The waterfall drops into a deep pool at the end of the long canyon.
The slot canyon has two circular caverns; the first can be reached via a narrow ledge above the creek on the right, or by wading up Centennial Glen Creek (the water is about chest-height). To reach the second cavern and base of the waterfall, you need to enter the water.
The plunge pool below the waterfall is a couple of metres deep, and even outside of summer the spectacular gorge entices people to brave the cold water and go for a swim.
Getting to The Grotto at Centennial Glen
The Grotto is reached via a fairly short but steep track down from the Centennial Glen Carpark, which is signposted. Centennial Glen Carpark is at the end of Centennial Glen Road (off Shipley Road) in Blackheath and is 1.7km drive or walk from Blackheath station.
Upstream of The Grotto is the Centennial Falls, and a very short distance downstream are the Slippery Dip Falls. You can visit all three waterfalls on a 2.5km loop walk, or on the longer Porters Pass and Colliers Causeway loop.