As citizens of the United Kingdom and others around the world mourn the death of Queen Elizabeth II, many have reflected on how the world has changed during the seven decades of the queen’s reign—the same decades that saw the rise of civilian nuclear power.

Calder Hall was already under construction at the Sellafield site in West Cumbria when Princess Elizabeth became queen in 1953. Queen Elizabeth traveled to the site in October 1956 and declared, in a televised ceremony, that “It is with pride that I now open Calder Hall, Britain’s first atomic power station.” Watch the fanfare in a historical clip uploaded to YouTube by Sellafield Ltd below.