The Panama Canal is one of the most impressive engineering feats in history, saving ships nearly 8,000 miles of travel by connecting the Atlantic and Pacific Oceans. Its original locks, completed in 1914, use a system of massive gates and chambers to lift and lower ships by 85 feet to match the level of Gatun Lake.

Here’s the fascinating part: the locks are so efficient that a 50-million-gallon water transfer happens with each passage—without pumps! It’s all done through gravity, making it a sustainable and ingenious design for its time.