The Lecture Hall was built by Chester Zoo staff and was named after Mrs Geraldine Russell Allen, who had recently resigned as the zoo’s Chairman of the Council. She had been a great supporter of the zoo from the very early years and was a founder member. His Royal Highness the Duke of Edinburgh performed the opening ceremony on 24 April 1972. After the official opening, the Duke of Edinburgh was taken on a tour of the zoo by George Mottershead and Professor King, who succeeded Mrs Russell Allen as Chairman. Image: The Duke of Edinburgh in the Tropical House with George Mottershead and Professor King, credit Kenneth Green