There is a gate at the Creux-de-Genthod bus stop. I walked past it many times but thought it was private property. Then one day Krista told me about a secret passage to the lake. So I took the kids to find it.
Shortly past the gate there is a path on the right hand side.
At the end of the path is a gate to a tunnel.
When you look in the tunnel, you see dark, and some trees at the end. It seemed very axe murder-ish, but we went in. Also, if you are wondering the tunnel goes under a main road.
Exit the tunnel and voila!
Boats and a dock....
And a beautiful view.
The dock is open to the public (if you know about it) and you can also bring your dog to swim in the lake. Off of the dock was a ramp for the dogs to walk up and down. There isn't much of a shore, but I think its a pretty cool place, maybe even good for a private picnic.