The democratic socialist movement is growing fast, fueled by people in their 20s and 30s and due in part to Senator Bernie Sanders' 2016 presidential bid. But what exactly is socialism? This is the last in a series of listener-requested topics. | Want to support 1A? Subscribe to our podcast and give to your local public radio station at donate.npr.org/1A. Email the show at 1a@wamu.org.