Narrated by the legendary Sir David Attenborough, this hour-long film follows the conservators, engineers and staff at the Natural History Museum as they take on an enormous task – removing the museum’s famous cast of a dinosaur skeleton (a diplodocus aka Dippy) in the entrance hall and replacing it bone by bone with an incredible skeleton of a blue whale, the largest animal to have lived. The task must be done without closing the museum to the public and there’s almost a disaster when a crucial bolt is sheared off mid-hoist, leaving the 4.5 tonne skeleton hung precariously in the air. The whale came from the coast of Ireland and died 126 years ago.