From the Guidebook:
In 1884 Frank Brown built
an unusual dam here to supply irrigation water for the
Redlands area. The single-arch granite dam formed Big
Bear Lake, then the world's largest man-made lake. Engineers
claimed the dam would not hold, and declared it "The
Eighth Wonder of the World" when it did. The old
dam is usually underwater because of the 20-foot higher
dam built 200 feet west in 1912.
Plaque placed by the State Department of Parks and Recreation in cooperation with Billy Holcomb Chapter of E Clampus Vitus, U.S. Forest Service, San Bernardino County Museum, and Big Bear Valley Historical Society. October 10, 1982.