Punamii-Uunpuu (Mitchell Falls) - WA

The falls are a 4.3 km walk from the main campgrounds. Allow 2.5 hours each way. Some visitors walk one way to or from the falls and take a helicopter flight in the other direction. The walk is best done in the early morning to dodge the heat. Parts of the trail involve uneven ground, water crossings and scrambling over rocks. It has a Class 5 rating and requires a high level of fitness. Access starts in May/June with the most water but it will be a trickle by September.
You need to wade the river (thigh deep) to see the falls in all their majesty from the western side before 2pm but the east side view is best in the late morning light.