Ralph Clark has a job that, hopefully, will someday soon disappear. He is CEO of Shotspotter, a system that listens for and triangulates shots fired in cities, jungles, and forests. His system, live in 90 cities, is essentially a quick and easy way for police to listen for dangerous situations and respond as necessary. He talks about Smart City World Expo Congress in Barcelona and we discussed the future of gun violence and the problems facing modern cities.