Jeff Koons's "Play-Doh" is a wondrous, 11-foot-tall sculpture. Inspired by a Play-Doh pile given to the artist by his young son, the sculpture actually consists of two dozen aluminum shapes that were cast in a plaster mold and lock together. After working on it for 20 years, Koons debuted the work at the Whitney Museum in 2014. Play-Doh is the largest piece in his Celebration series that also includes the iconic Balloon Dog and Tulips. One of the five unique versions of the sculpture sold at a Christie's last year for $20 million.