The Royal Tasmanian Botanic Gardens are beautiful. They feature some uniquely Tasmanian plants and have a gorgeous waterfront location/view.
One of their biggest attractions is the Subantarctic Plant House. The small house is cooled and fanned to feel like the frigid climate of Antartica, so that the native Antarctic plants can grow there. The habitat is meant to specifically be like Macquarie Island.
It was definitely cold inside and the realistic mural that blended into the actual plants really immersed you into Antartica. Everything was a lot more green than I imagine Antartica, but Macquarie Island is pretty far north for Antarctica (about halfway between Tasmania and Antartica).