Taken during the afternoon crossing of the Panama Canal at Gatun Locks on a cruise ship.
Panama Canal once the Canal Zone administered by the US now part of Panama. Gatun Locks is 1 of 3 sets of locks close to the Caribbean side of Panama. Ships need to schedule their crossing ahead of time.
Most cargo ships are narrower than the width of the locks while larger ones have to go around Cape Horn at the tip of S. America (an additional 3000 miles). Ships are tied to trolleys on both sides with long cables to guide them safely through the locks.
Before reaching the next set of locks ships wait for their turn at Gatun Lake (a man-made lake) in the middle of Panama. It take a few hours to get to the Pacific side.