Here are a few images from the opening day ceremonies of the One Young World Summit in Downtown, Pittsburgh on Thursday, October 18, 2012. The festivities began with a keynote address by President Bill Clinton who addressed the over 1,300 young delegates from 182 countries around the world. One Young World is a charity that stages an annual Summit, gathering together the brightest young people from around the world. The third annual One Young World Summit is being held in Pittsburgh from October 18-21st.