The Incas of ancient Peru were no strangers to El Niños. Inca rulers built stone storehouses on steep hillsides to protect food and supplies from El Niño floods. El Niño may have also aided Spain's conquest of the Inca Empire in 1532-33. Spanish soldiers wrote about the constant rains in Peru's desert north coast. They probably fed their horses on desert plants that only “green-up” during El Niño rains.