Did you know that Italian, German and Austrian POWs were held on the island during WWI and WWII? And that women served in the forces there during WWII?
And it has a dark history as a prison for Aboriginal men and boys for over fifty years. They built many of the older buildings and were used in farming activities on the island but many died from influenza and the measles.
Did you know that you shouldn't feed the quokkas anything except the Rottnest tea-tree, because other things like bread could make them sick?
Whether this is your first visit or your fiftieth, it's worthwhile doing one of the free walks on the island conducted by the knowledgeable Rottnest Voluntary Guides Association guides. You can find what tours are on here.