It is not just the magnificent architecture of churches and cathedrals that has fascinated people over the centuries, but also the splendour of their windows. The scenes they depicted not only taught the illiterate the stories of the bible and the lives of the saints. In the play of sunlight, they joined forces to create the vision of a place that was much more than just a church building. In the Gothic era, which saw the first great period of stained glass, these windows transformed church interiors into symbols of the 'heavenly Jerusalem,' the magnificent celestial city in the apocalyptic visions of St John. Stained-glass windows have continued to develop their own visual vocabulary right up to own times. With examples such as the famous windows of Cologne Cathedral and other churches, this film shows how stained-glass specialists, from the unknown medieval masters to famous contemporary artists such as Gerhard Richter and Markus Lüpertz, have created sacred spaces and moods, using just colour, glass and light.