'Ooh, it’s so big'… First-time visitors gush as they strain their neck muscles gazing up to the Münster. It is. And rather beautiful. Celebrated for its 161.5m-high steeple, the world’s tallest, this Goliath of cathedrals took a staggering 500 years to build from the first stone laid in 1377. Note the hallmarks on each stone, inscribed by cutters who were paid by the block.