After the great Fire of London in 1666, the people of London did indeed rebuild the city. The English architect Sir Christopher Wren was instrumental in the rebuilding process and designed many of the new buildings, including St. Paul's Cathedral. The rebuilding took several decades to complete, but the new London was a significant improvement over the old city. The streets were wider and straighter, and many of the buildings were made of brick instead of wood, which made them less fire-prone. The new London was also more prosperous and cosmopolitan than the old city, and it quickly became one of the most important cities in the world.