6. The Compass

The arrival of the magnetic compass in medieval Europe was a game-changer for navigation. Originally developed in China, the compass found widespread use among European mariners by the 12th century. This simple yet powerful tool allowed sailors to determine direction even on cloudy days or at night, vastly improving the safety and scope of sea travel. The compass paved the way for the Age of Exploration, enabling daring voyages that expanded trade and reshaped the world.