 Ludwig Leichhardt was the first land-based European explorer to visit the Kakadu region, in 1845 on his route from Moreton Bay in Queensland to Port Essington in the Northern Territory.He followed Jim Jim Creek down from the Arnhem Land escarpment, then went down the South Alligator before crossing to the East Alligator and proceeding north.A more plausible, if prosaic, explanation for the origin of the name of the park is that Leichhardt applied the colloquial German term for a cockatoo, although this is unlikely to sit well with the indigenous historians.