UCLA History: Where's the bridge?

The roadway that connects the plaza between Dodd and Murphy to the one between Royce and Powell carries the sign above referring to a bridge.  Many in the UCLA community know the history but for those who don't, the seeming roadway is in fact a bridge over a ravine that was long ago filled with dirt.  When the Westwood campus was being constructed, however, the ravine was a prominent feature and the bridge was one of the early structures built as the photo below shows.

When the campus opened in 1929, crossing the bridge was a common occurrence as show in the 1930 photo below..