Why do we create on the walls around us? From French cave paintings created some 17,000 years ago to political graffiti on the streets of Pompeii, humanity has always longed to make art for everyone to see. Whether commissioned or not, the art we share is essential to who we are.

There’s no better place to see this in practice than in Philadelphia. It’s the birthplace of the modern-day graffiti movement, home to the largest public arts program in the nation, and is often called the “Mural Capital of the World.” Join host Conrad Benner, founder of the Streets Dept blog, as he speaks with some of the most prolific street artists in the city about why their work is so vital to their lives, and ours.