The Blue Carousel was a transportation themed carousel that first operated at Alton Towers in 1981. Vehicles from across the years were available for young guests to ride in, with options ranging from an olde world horse and carriage through to a classic car and caravan combo. All the vehicles were attached to a large spinning disc, which span below a distinctive blue canopy.
In 1982, the area where the ride operated at the end of Talbot Street became known as Adventureland 4-11, and the Blue Carousel continued to operate in this area for the remainder of its time at the park.
After a decade at Alton Towers, The Blue Carousel was removed in 1991, when Adventureland 4-11 closed. It was effectively replaced by the Gallopers (now the Royal Carousel), which opened in nearby Talbot Street in the same year. After departing Alton Towers The Blue Carousel went on to operate at Flamingo Land, via a brief stint at Pleasure Island in Cleethorpes.
But the story didn't end there... The remains of the carousel's foundations are still in situ backstage at the park today. When The Blue Carousel was removed, Adventure Land 4-11 ceased to be a guest area, and was instead used for backstage purposes. But, because the area was located within a copse of trees, the park was somewhat limited with how much of the area they continued to use, and therefore some of the Adventureland 4-11's infrastructure still remains today.
It is likely that these remains will finally be removed during the construction of Project Horizon, with the new ride's queue line designed to cut through the area (although technically the plans do not call for their removal specifically).