Topic 5: San Francisco’s $6 Billion Sinking Artificial Island
Right now, you're looking down at Treasure Island from the Bay Bridge, and here's the crazy part: this island isn't even real. San Francisco is about to spend six billion dollars building a brand-new high-rise mini-city here, with up to ten thousand eight hundred homes, on a 400-acre pile of wet sand and bay mud that was dumped here in 1939. It's sinking right now, and in a big earthquake, it can turn into liquid. So how do you build a city on that? Stick around, because the answer is wild, and it starts with a pile of mud. Let's start with how this place even exists. Back in the 1930s, workers dredged sand and mud from the bottom of San Francisco Bay, piled it on a shallow shoal next to Yerba Buena Island, and wrapped the whole thing in a rock wall. The plan was to host the 1939 World's Fair, and then turn it into an airport. That never happened. The Navy took over, ran a base here for decades, and left in the 1990s. So today, the city owns a flat, windy patch ...