When it comes to our love of cities, there’s both good news and bad news: Cities have the distinction of being both engines of economic growth and the main culprits behind climate change and economic inequality. While cities occupy less than 2% of the world’s land surface, they are home to 60% of the population and nearly 80% of the carbon emissions, according to the UN. They contain deep pockets of poverty, a diverse middle class and a sliver of extremely wealthy individuals.

Here, we take a closer look at opportunities to reinvent cities as we know them through both high-tech and low-tech initiatives.