The gardens were opened in honor of Queen Victoria 's Diamond Jubilee , and contained a large lake , and what can only be described as a small early version of a roller coaster , known as a switchback . The gardens were opened in honor of Queen Victoria 's Diamond Jubilee , and contained a large lake , which covered 3 a , and what can only be described as a small early version of a roller coaster , known as a switchback ( an alternative general term for a roller coaster ) .