Castlewood Canyon State Park near Franktown preserves a varied landscape of grasslands, shrublands, riparian areas, conifer habitat, and caprock formations on the edge of the Palmer Divide. It is most notable for the ruins of Castlewood Canyon Dam, built in 1890 and destroyed after heavy rains early on August 3, 1933, sending a 15-foot wall of water down Cherry Creek toward Denver. Warnings allowed most people to escape the flood’s path, and the disaster became an enduring part of Colorado history. Established as a state park in 1964, the area also includes the historic Cherry Creek Bridge and the Cherry Creek Rockshelter archeological site.