Today we're going to talk about how and why floods happen both in spite of, and because of, us. Specifically, we'll take a closer look at the island of Java, and its largest city, Jakarta, and explain the factors that lead to serious flooding almost annually. We'll also show you how mangroves can help protect us from flooding, and how wetlands along floodplains act like the kidneys of the Earth filtering out impurities and pollutants.