As part of Dr. Charlie Schroeder’s revitalization of the Zoo, he added a new grotto exhibit for the Zoo’s polar bears, Frieda, Hilda, and Olaf, in 1960. It included a pool that was 25 feet long, 14 feet wide, and 6 feet deep; a slide and diving platform; and white walls to simulate ice. From time to time, Dr. Schroeder would order huge ice blocks to go in the pool. When the bears moved in, Frieda and Hilda, the two females, were more active in exploring their new home, while 650-pound Olaf, the male, did a cursory walk-around before settling down for a snooze in the sun.