Even before the modern skyscraper, the super tall building has been a source of innovation and fierce competition – and no time was the fight for height fiercer than in the late 18th century when cathedrals across Europe competed to make their spires the tallest. Cologne was the tallest building in the world for 4 years – but where did the money for these religious super spires come from? And just how fierce – and dirty - did the fight become? Presented by Charlie Luxton.