Gothic cathedrals
In some parts of Europe, there were many tall straight trees that were good for making very large roofs. But in England, by the 1400s, the long straight trees were running out. Many of the trees were used for building ships. The architects had to think of a new way to make a wide roof from short pieces of timber. That is how they invented the hammer-beam roofs which are one of the beautiful features seen in many old English churches.