Kakadu national park is a natural wonder with sublime landscapes, including rocky formations, canyons, luxurious forests, exceptional plant and animal life and breathtaking colours. I went there on a day trip from Darwin and I was disappointed that I couldn't do more and explore the park more - the tour took us to certain pre-determined spots.
I think you need at least a few days to make the most of this park's riches. It has one of the biggest concentrations of crocodiles and is unfortunately menaced by industrial mining which has turned its sights on this region so rich in resources. Definitely a must see on your Australian trip.
I really enjoyed the park, which is both a nature reserve and a World Heritage Site. Kakadu actually has one of the world's highest concentrations of Aboriginal cave art. Paintings of animals, hunters, handprints and the depiction of characters from the 'Dreamtime', which is the Aboriginal understanding of creation. Don't miss the sites of Nourlangie Rock, Anbangang and Ubirr Rock.
In terms of nature, we were able to spot many crocodiles, some "freshies" and some dangerous "salties". You can go on a cruise to get very close to them in complete safety. If you go on your own, make sure you respect the signs telling you not to swim everywhere, especially in the humid season when the waterways converge. The park is home to 1000 plant species, a quarter of all Australian freshwater fish species and more than a third of the country's bird species. Photographers will love it!
Finally, the landscapes are rather unique and change considerably from one side of the park to the other. Landscapes worthy of Indiana Jones, with peaks and hills, swamps ("billabongs"), tree-filled savannahs and canyons. The sites, which strike me as unmissable, are Maguk Gorge and Jim Jim Falls. But do not forget to protect yourself from the sun and against insects.