The Spanish treasure fleets were groups of ships that transported valuable goods, such as gold, silver, and spices, from the Americas to Spain during the 16th to 18th centuries. These fleets were crucial for the Spanish Empire, as they helped maintain its wealth and power through trade and colonization. The treasure fleets typically sailed from ports like Havana in Cuba to Seville in Spain. They faced many dangers, including storms and attacks from pirates, making their journeys perilous. Despite these challenges, the fleets played a significant role in the economic history of Europe and the Americas.