Britain's Most Fragile Treasure

Janina Ramirez explores the complex history of York Minster's Great East Window, the largest medieval stained-glass window in England. Composed of 311 panels, it was originally designed to tell the complete biblical history of the world from creation to the Last Judgement, and has been compared to Michelangelo's work at the Sistine Chapel. The historian closely examines the handiwork of its creator John Thornton, revealing intricate details that would not normally be visible, and follows a project to restore the window to its original glory