19.20.21 — short for 19 cities with 20 million people in the 21st century — is a new five-year study that will analyze the impact of supercities on our global future. Of particular interest are maps on the 19.20.21 site showing the world's largest cities throughout history. The project comes from Richard Saul Wurman, creator of the TED conference and the term "information architect."
Editorial note: Whoa! You've found a super-old post here on BuzzFeed, from an earlier era of the site. It doesn't really represent where we are anymore, and may in fact be totally broken, but we're leaving it up as a part of our early history.