No key required, just add water, well control the waterlevel as there will not be enough to let it go freely.

Locks are just as those traffic lights but then on a river, well actually mostly on canals.

You will find fish slapping dance performers on the quays alongside the locks. Actually fish ladders are to be found near some locks.

Lock

The idea is the water keeps locked in the canal, while vessels can pass the lock. Modern low difference lock consist of two pairs of doors enclosing a small part of the canal. By opening only one pair of the doors at any time the amount of water spilling down stream is limited. The doors will open in the upstream direction, this makes the water pressure help them to keep closed. In the face of the doors there will be a