The Pirate Cave is a unique Infrastructure building in Tropico 2: Pirate Cove that is used to collect your hoard, a victory goal in most campaign missions. You should set it to "Stash Maximum" at the very beginning of any game where this is a goal. Even with stash maximum, it will only collect 25% of the gold that you receive from cruises. It also stashes a corresponding percentage of gold collected from the Smuggler's Cove and spent by pirates and wealthy captives at Entertainment Buildings.