This is a picture of what it looks like to be inside of a lock:
These locks were built in the early
1800's. They were state of the art then and were technologically
ahead of their time.
As you can see these locks were
constructed of many individual blocks of stone. Many masons were
involved in building a lock.
They identified themselves with
something called mason marks.
This is a picture from the sign inside the lock:
These are what mason marks look like:
