US 101 is probably the most historic highway in California. It follows the route the Spanish explorer Juan Gaspar de Portola followed in 1769, which later became El Camino Real, the King's Highway. This historic road connected the 21 missions of California and served as the main north/south road in California until the 1920s. North of San Francisco it is known as the "Redwood Highway," which is considered by many to be the most scenic road in California. At one time its route followed the famous Avenue of the Giants, which goes by the tallest trees in the world located in the Redwood State and National Parks. Even though this road was surpassed by US 99 and later I-5, it remains an important road linking cities along the coast of California.