[74, Amiens Cathedral] Gothic churches were taller and brighter than the earlier Romanesque. They were made with a skeleton of support. The key to Gothic is the pointed arch. A Romanesque church is built with round arches. With a round arch, the weight pushes down. But with a pointed arch, the weight pushes not down but out. As a tour guide, it's fun to demonstrate this by building a Gothic cathedral out of tourists.

[75] You start with six columns. These will support the roof with ribs (ignore the elbows) coming together with pointed arches. The key to Gothic is the pointed arch. A Romanesque church is built with round arches. With a round arch, the weight sits squarely on the wall and it needs to be thick and strong. If a round arch collapses, it falls down. But, if you point the arches, suddenly the weight of the roof pushes not down but out. So, rather than thick walls you need to buttress the building by adding support pushing in. So, you need six more tourists to be buttresses. With buttresses rather than thick walls supporting the church, the walls are freed to become window holders — letting in more light. To free up even more wall space, you can make the buttresses "flying buttresses" with their support "flying" in with more arches.

Rick: Are you guys ready for a spire?
Tourists: Yes, we are!

Now, when the spire is raised, because of the pointed arches, the weight goes out rather than down and, with buttresses in place, everything is solid — windows can fill the spaces between the columns — and you've built a Gothic church out of tourists.

Rick: Alright, thank you! That was good!
Tourist: One more time! One more time! [laughter]