Fremantle Prison is Australia's most intact former convict establishment. After 140 years in operation, it only closed its doors as a maximum security jail in 1991. Fremantle Prison opened to the public one-year later and welcomes thousands of visitors annually. There are interesting tours daily and interactive exhibits, too.
Perth's Kings Park is bigger than New York's Central Park. Visit its 750-year-old boab tree, walk over the treetops on a suspended bridge, see the State War Memorial, take photos of the Swan River and skyline or do one of the various daily free walking tours on offer.