Lecture — why cities keep growing

Lecture summary: The speaker explains that cities grow because they lower the cost of finding work, customers and ideas. Doubling a city's population raises productivity per person by roughly 15% in the data cited. The costs are congestion and housing prices, which the speaker argues are planning failures rather than inevitable results of size. Re-tell the lecture in your own words. You have 10 seconds to prepare and 40 seconds to speak.