California, US
Fernbridge, originally Eel River Bridge, is a 1,320-foot-long (402.3 m) reinforced concrete arch bridge designed by American engineer John B. Leonard which opened on November 8, 1911 at the site of an earlier ferry crossing of the Eel River. Fernbridge is the last crossing before the Eel arrives at
the Pacific Ocean, and anchors one end of California State Route 211 leading to Ferndale, California. When built, it was referred to as the "Queen of Bridges" and is still the longest functional poured concrete bridge in operation in the world.
Listen to the audio guide for Fernbridge Free on WIP — starts by itself when you arrive, even with the screen off