The Santa Fe Arroyo Seco Railroad Bridge in Highland Park, Los Angeles, is more than 710 feet (220 m) long and crosses the Arroyo Seco Parkway at an elevation of over 56 feet (17 m). It is the tallest and longest railroad span in the city of Los Angeles, and most likely the oldest such structure still in use.The bridge crosses the lower part of the Arroyo Seco, a watershed canyon from the San Gabriel Mountains. Advocated by the Highland Park Heritage Trust and Charles J. Fisher, the bridge was declared City of Los Angeles Historic-Cultural Monument No. 339 on January 22, 1988. * * * *