Bill Gates with Living Proof Graffiti at the Brandenburg Gate in Berlin

Bill Gates continued his Living Proof tour of Europe by making his mark at the Brandenburg Gate in Berlin with the help of a group of ONE Youth Messengers. The graffiti artwork, by local Berlin artist Alias, is to support Living Proof, a global health program that pushes for "smart aid" investments in global health and development. The Youth Messenger are a group of young activists chosen by the ONE Campaign to share the proof about smart aid in their communities by working with local media, and by engaging their social networks, both online and offline.