The River Duero is a significant river in the Iberian Peninsula, flowing through northern Spain and into Portugal. It spans approximately 897 kilometers, making it one of the longest rivers in the region. The river is known for its scenic landscapes, including vineyards and historic towns, particularly in the Douro Valley, which is famous for its wine production. In Portugal, the Duero is called the Douro and is a vital waterway for transportation and agriculture. The river eventually empties into the Atlantic Ocean at the city of Porto. Its basin supports diverse ecosystems and is crucial for local economies, especially in agriculture and tourism.