3. Panama Canal
The Panama Canal, completed in 1914, is a 50-mile (82-kilometer) artificial waterway that connects the Atlantic and Pacific Oceans across the Isthmus of Panama. This engineering marvel significantly shortened maritime travel, eliminating the need for ships to navigate the lengthy and hazardous route around South America. Its strategic importance is underscored by its role in global trade and military logistics, with disruptions having far-reaching economic and geopolitical consequences. (history.com)
