An important tributary, Verdugo Wash, flows in from the left. The Verdugo Wash begins in the Verdugo Hills and flows west to the Los Angeles River. Uniquely, the intersection of Interstate 5 and Route 134 is located right above this point. The Los Angeles River makes a great bend west around Griffith Park, a big park in the middle of Los Angeles. Here, the river has an earthen bottom, which is unique because most of the river is covered with concrete. Further downstream, there is a place uniquely named "Frogtown" because of the many frogs once found in the river there. Downstream from this place, the river picks up another important tributary, Arroyo Seco, on the left. (The name "Arroyo Seco" means "dry creek" in Spanish.) The Arroyo Seco begins in the San Gabriel Mountains and flows south to the Los Angeles River. One important feature of the Arroyo Seco is the giant Devil's Gate Dam. The Arroyo Seco is free-flowing in many places.