Gunlom Falls

South of Kakadu - about 4hours drive from Darwin to the turn off, then about an hour on a dirt road, very bumpy - 4WD only. Amazing view from the top of the falls, they call it a natural infinity pool. It's a rock scramble to get up, can take a fit person 20-30 mins. Worth it! Very good for sunset, but bring your head torch for the climb down in the dark, its not easy. The lower falls are nice and sandy - very family friendly.
The upper pools have lots of little plunge pools, but can get busy - best to go early morning or stay for the sunset.
There is camping here, but I've never stayed - we stay at Cooinda Lodge.