I have two days to spend solo in Brisbane and am looking for the must-see attractions, museums, monuments, neighborhoods, etc unique to the city.
Sorry to be so general about this, Leah ... but I had the same amount of time in Brisbane. All I did was walk around the city center and stumble on cool place after cool place. There's a river running through the city, and you can pick up the CityCat and ride it to all sorts of places along the river. The Queen Street Mall is a lot of fun, and so is the Brewhouse Brisbane. The Queensland Museum was fun for a few hours. If you're there at the right time (like September), the Brisbane Festival really wakes the whole city right up!
Justin is right on the money - just wander around Queen Street Mall, South Bank Parkland and Fortitude Valley. There are some great alleyway bars, good food and even a man made beach you can swim in right in the middle of it all!
For something unique (depending on budget) you can abseil the Kangaroo Point Cliffs, do the Story Bridge Adventure Climb, have a drink at Alfred & Constance and Cloudland and enjoy an Aussie Angus steak at Black Hide Steakhouse ($$$$$) or Breakfast Creek Hotel.
Otherwise, just walk. Walk from Queen Street Mall to the Botanical Gardens, then across the Brisbane River to Kangaroo Point. Follow the river (to the right) and walk along South Bank Parklands. At the other end is GoMA (Gallery of Modern Art) and some pop up markets.
Catch great live music at Lefty's Old Time Music Hall or watch a sporting game at Suncorp Stadium (I recommend the Brisbane Roar for Soccer, Brisbane Broncos for Rugby League or Brisbane Reds for Rugby Union).
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