On our “Grand European Tour” river cruise last summer, we went through a total of 63 locks! I guess many of them were at night, but we also experienced going down and up in locks quite often in the daytime also. This was my perspective (taken from the balcony of our stateroom) of descending into a lock.
Wanderlust & Wonderment 
That’s a lot of locks, guess though they were automated. I once did 29 in a morning, all by hand. tad tired by the end of it!
Wow, I can’t imagine by hand! (The locks at the Panama Canal are more sophisticated, very high tech, with little train trucks attached to each side of the ship, going up and down a railroad track, to keep the ship centered and moving at a certain speed.) I guess there are a lot of changes in elevation in the European rivers we travelled, thus necessitating so many locks. It does slow down river traffic though!
Fortunately our locks are no where near as big as these, very narrow canal locks