Katy Perry is set to release her album Prism in October, and in case you forget, there was a huge golden semi-truck with the date on the side driving around the country this summer. The first stop for the truck was Los Angeles and Perry sent out the notice to her fans via Twitter: "Find the semi, take a picture and I'll RT you. Don't worry, Los Angeles is just the first stop on the map." These photos of the singer and the truck were also posted to Twitter. We never did see it in person, so no retweet for us (sad face).