CommBank: Where's my wallet

To communicate CommBank's Cardless Cash technology M&C Saatchi Sydney took the largest panoramic shot of Sydney ever taken (125 Gigapixel) and hid 100 wallets through the city’s nooks and crannies. In an interactive game, users zoomed in and out, panning around the city searching for one of the 10 daily wallets. If they found one, they won $200. The prize money was redeemed through a unique code that allowed them to experience Cardless Cash from any CommBank ATM.
During the 10 days of gameplay it received 43,000 unique visitors that spent on average 12 minutes on the site, while winners took on average 64 minutes to find a wallet on the 9th day, the average was 133 minutes!