The River Douro is one of the major rivers in the Iberian Peninsula, flowing through Spain and Portugal. It stretches approximately 897 kilometers, making it the third-longest river in the region. The river is known for its scenic landscapes, including steep vineyards and picturesque towns, particularly in the Douro Valley, which is famous for its Port wine production. The Douro begins in the Sierra de Urbión mountains in Spain and travels westward, eventually emptying into the Atlantic Ocean near Porto, Portugal. Along its course, the river has played a significant role in trade and transportation, contributing to the cultural and economic development of the surrounding areas.