The Panama Canal is a man-made waterway that stretches across Panama. It was built to connect the Atlantic and Pacific Oceans, so ships don't have to sail all the way around South America to get between the two oceans. The Canal is made up of three big locks (basically doors in the water) with a big pool of water in between them. When a ship enters the Canal, it passes through the first lock and into the pool. Then, that pool is filled up with extra water from the second lock, and then the ship enters the second lock - this is called "going up" because the water is rising. Then the ship enters the third lock, and then the pool is emptied, which is called "going down" because the water is going down. Finally, the ship goes through the third lock and exits the Canal.