Check out this amazing photo of a wooden elevated flume at Lake Cuyamaca, which was set up to provide water for the city of San Diego! Stretching about 37 miles, it was constructed by the San Diego Flume Company between 1886 and 1889. They brought in redwood lumber by boat to the San Diego harbor, cut it to size, and then loaded it onto wagons for the trip inland. Can you believe it? A total of 315 trestles were involved to carry the flume over valleys, canyons, and ravines! The flume's usefulness eventually was replaced with other water sources and today there are very few remnants of the old line remaining.