Cadwalader Park, established in 1888 and designed by Frederick Law Olmsted, Sr., became a popular community park in Trenton where generations gathered for childhood games, family picnics, athletics, parades, outdoor events, and community celebrations. Its attractions changed over time and included a skating pond, an observation tower, a carousel, a playground, pony rides, two lawn-bowling greens, and a zoo. Soon after the park opened, citizens donated small animals and birds, and the old stables and farm buildings of the Ellarslie estate were converted to house deer, sheep, elk, monkeys, and a black bear cub. Although Olmsted objected to reserving park space for animals, the zoo remained popular, and by 1913 the city had added a new deer paddock and barn in the west ravine and a monkey house, bear pit, and aviary near Ellarslie mansion. In the 1930s, Ellarslie mansion itself became a monkey house for a growing collection of primates, and at various times the zoo also sheltered prairie dogs, burros, alligators, peacocks, foxes, snakes, buffalo, and a kangaroo. Early park features also included a 50-foot-tall timber observatory and an ice-skating pond dug in 1897 in the lower park. As times changed, some attractions disappeared and were replaced by others, including a natural history museum and ice cream parlor in Ellarslie, a playground with carnival rides, a greenhouse, and a Japanese garden. Financial cutbacks in the 1960s and 1970s led to the removal of many facilities, but the park remained strongly tied to the memories of city residents.