guys pls help rockstars sense of humor in one image: a door with a sign saying No Hidden Content Here, and behind it, hidden content.
in GTA IV, Happiness Island's statue has a hidden interoir... climb up the ladders and u'll see a giant beating heart wrapped in chains... you can hear it pumping.
u can reach the island early on by boat or helicopter. Its a perfect quick secret to show someone who has never seen it, and it still holds up visually.