Play mission 14, "Sin City". You must destroy a total of twenty one slot machines to earn this trophy. The first twenty are on the lower casino floor. The final slot machine is found after going through the gate that Keegan pries open. The team will lead you down a curving escalator. Before going down the escalator, look across to the Majestic lobby and find the two Egyptian women on a billboard with a stylistic sun. The final row of slot machines that are destroyable are located to the left of this billboard.