The goldfish pond at the mansion has existed since the mansion was built. Its circular section was the original part, built in 1910, and its long rectangular portion was added in the 1920s. The circular part originally housed Pawnee Bill's pet alligator, an animal used in his Wild West Show. After the alligator died, it was made into an umbrella and cane rack and placed inside Pawnee Bill's office. Beside the pond stands the mansion's original windmill tower, which when built in 1910 provided water and electricity for the mansion. After Billy Lillie's tragic death on the tower in 1925, Pawnee Bill added a large wooden cross to the top so the structure could be lit on major holidays, a tradition continued in memory of their son. The original wooden cross is gone, and a metal one installed in the 1970s stands in its place. The fishpond was a highlight of the Lillie mansion, surrounded by May Lillie's rose bushes that still grow today, while peacocks commonly roamed the lawn around the fishpond and windmill tower.