Area full of interesting rock and lava formations and nice views. Also a great place for bird watching. There're two free parking lots.
One providing you with some nice views straight after parking the car and the other one will lead you to the forested peninsula where you'll find couple of short routes that will take you to more interesting rock formations and hidden lagoons.
But if you're short on time, here's a tip. When you enter the forest and walk through the gate, take the first turn right. That will shortly take you up to the little view point from where you can perfectly see the entire lake. (as you can see on one of the photos)