Preservationists led by Muir and the Sierra Club failed to save Hetch Hetchy Valley from becoming a reservoir in 1923. In 1964, 89 percent of the park was set aside in a highly protected wilderness area, and other protected areas were added adjacent to the park. The once-famous Yosemite Firefall, created by pushing red hot embers off a cliff near Glacier Point at night, was discontinued in the mid-to-late 20th century along with other activities that were deemed to be inconsistent with protection of the national park.