An astonishing discovery has been made at Canterbury Cathedral: possibly the world's oldest space frame, dating to 1180 AD. This could put the invention of this engineering solution (until now attributed to Alexander Graham Bell and Buckminster Fuller) back by a cool 700 years. An external grille attached to a huge wrought iron window frame had previously been supposed to date to the 19th or even 20th century. When scaffolding was erected in 2006, conservators and the cathedral architect inspected the grille close up and discovered that it was in fact part of the original late 12th century construction. The frame and the stained glass are currently undergoing conservation. Structural analysis of the space frame has shown that it is still strong enough to survive for centuries to come - providing it is carefully maintained. The conservation of the medieval metalwork was generously supported with a grant from the Worshipful Company of Ironmongers.