In 1325, the Mexica (Aztec) people founded their capital city, Tenochtitlan, on an island in Lake Texcoco. According to legend, they chose the spot after seeing an eagle perched on a cactus devouring a snake—an image that remains the centerpiece of the Mexican flag. Tenochtitlan was a marvel of pre-Columbian engineering, featuring a complex system of causeways, canals, and 'chinampas' (artificial floating islands for agriculture). At its peak, it was one of the largest cities in the world, with a population estimated between 200,000 and 300,000. The city was organized around a central sacred precinct dominated by the Templo Mayor. Its sophisticated urban planning and hydraulic systems allowed the Aztecs to maintain a massive population in the middle of a lake, making it a pinnacle of Mesoamerican civilization before its fall to Spanish forces in 1521.