Twenty-seven bridges span the entirety of the Los Angeles River from the San Bernadino Valley down to Long Beach, fourteen of which are within the Los Angeles city limits. Built in a less than three decades between 1909-1938, the bridges represent a significant time period for Los Angeles, when the combination of a population explosion and the popularity of the automobile redefined the young city. In an attempt to alleviate the number of cars on surface streets and the complicated traffic jams that had started to pop up, the city built the bridges to redirect traffic flows. Their massive scale and impressive architecture was influenced by the nationwide City Beautiful Movement of the time, which sought to improve the morale and civic engagements of citizens by beautifying the city around them. Evolving in architectural style over time, a tour of the bridges is also an example of the stylistic preferences over the three decades that the bridges were built. Recently, the bridges have come under threat of demolition; some are considered on their way to being structurally unsound due to lack of preservation. However, a vote in 2008 by the Los Angeles City Council designated eleven of the fourteen bridges as Historic-Cultural Monuments--delaying, if not stopping, their possible alteration.