How do you creatively plan for a population of 62 million by 2100? Australia's current major city planning frameworks only account for an extra 5.5 million people. Whether we want a 'Big Australia' or not, Australia's 21st century is likely to see rapid and continual growth - and if we want liveable, high functioning cities and regional centres we need to think outside the box. Richard Weller and Julian Bolleter (Australian Urban Design Research Centre) offer optimistic and creative solutions for the future with one imperative: what we build this century will make or break our country.