La Noche Triste — Spanish Routed from Tenochtitlan

Attempting to escape Tenochtitlan under cover of night, Cortés's force is discovered and attacked on the causeways across Lake Texcoco. In the running battle, the Spanish and their allies suffer catastrophic losses: over 450 Spanish soldiers and thousands of Tlaxcalan allies killed, most of the artillery and horses lost, and nearly all the seized Aztec treasure dropped in the lake as the soldiers tried to flee. Cortés is said to have wept under a tree at dawn — the famous 'sad night.' It is the worst Spanish defeat of the conquest.