Simplify the following text for a Grade 12 native English-speaking person.
Original: 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 .
Simplified: Ludwig Leichhardt was the first land-based European explorer to visit the Kakadu region , in 1845 on his way from Moreton Bay in Queensland to Port Essington in the Northern Territory .