The Fuji safari park in Japan, has opened a new swimming area for its herd of Asian elephants, incorporated into the pool is a glass wall for underwater viewing.
https://home.bt.com/news/odd-news/zoo-encourages-elephants-to-swim-11363992163512
https://home.bt.com/news/odd-news/zoo-encourages-elephants-to-swim-11363992163512