In 1921, Canada was one of the first countries to reach the half-urban milestone. The rest of the world, combined, did not reach 50% urban until more than 85 years later in 2008. In the 1920s, global population surpassed 2 billion. One hundred years later, the population had quadrupled to more than 8 billion. For the last 100 years, the world’s attention was often on the emergence of more than 75 new countries. Geopolitical tensions were intense at times, leaving cities somewhat overlooked. Yet, they led global wealth and waste generation, which increased more than tenfold as the world urbanized. Cities, especially Canadian cities, drove this Great Acceleration largely through their ability to scale. A city that doubles in size more than doubles wealth, energy use, and waste generation. The increase is superlinear (~ 1.15). That same city that doubles in size can also do so with less than twice the infrastructure costs. Infrastructure costs increase sublinearly (~ 0.85). Countries and businesses do not benefit from this scaling superpower. As cities scale, they evolve into large urban agglomerations with complex adaptive systems that behave uncannily like natural systems. Cities can benefit by applying the contributions of two key researchers: Dana Meadows and her places to intervene in a (urban) system, and Elinor Ostrom’s the city as commons.