Wallpeople is an urban art collective that brings large groups of people together to make art. Targeting one specific urban area, they turn on music and work together to create a unique outdoor art gallery. Though it started as a local thing in Barcelona, the Wallpeople movement has spread to more than 40 countries. On June 1st, thousands of people around the world came together to transform empty walls into lovely works of art. Watch one of their videos here to see what happened.