Requirements: Level 2 Construction
Action: Drop a villager on the rock pile on the top left of the map. Builders will work best but even if they are not a builder, they soon will be if you keep dropping them there. The villagers will pick up a rock and carry it to the extreme far side of the map. This puzzle takes time and I like to wait on this one until I get a large population and lots of food. When completed the lagoon will fill with water.
Description: "Your builders removed the creek blockage! The water now flows freely providing a pristine, pure stream. The waters of this lagoon may be the key to more than one mystery for your villagers."