Some ideas so far

Brisbane City Super Canopy, idea by Urbis
This image depicts rooftop gardens in the CBD as a way of enhancing shade and providing a rich habitat for wildlife in the city centre.
Frog's Hollow Civic Space, idea by FORM
Brisbane City Super Canopy, idea by Urbis
Subterrain, idea by Andrea Goodwin, Creative Road Art Projects
Seasonal River Pool, idea by Urbis
Gabba Plaza, idea by CUSP
Green the Queen, idea by ARIA/Urbis