The Australian Museum in Sydney is the oldest museum in Australia, founded in 1827. It is located in the heart of Sydney, near Hyde Park, and is renowned for its impressive collections in natural history, science, and culture.
The dinosaur gallery is amazing, as are the numerous cultural artifacts of the indigenous people of the Pacific Islands.
The museum is free but special exhibitions have to be paid. If the dinosaurs are not enough, there is also a very nice kids area.