You must first be able to travel to Happiness Island. Find the Helicopter Tours directly east of Happiness Island. Steal a helicopter and fly to Happiness Island. Hover over the Statue Of Happiness and jump out of the helicopter at the statue's feet. Try to land on the topmost tier of the statue, which is a square platform with a door in the center of each side. Run around the platform until you see a door with a plaque that reads "No Hidden Content Here". Walk through that door to enter an empty room with a high ladder. Climb it and look up at the top to find the statue's gigantic beating heart, held in place by chains.