St. Paul's Cathedral is worth visiting not only because it is the world's famous religious shrine, the fifth Cathedral in the world, and the first cathedral in Britain, but also because it is one of the few churches designed and built by one person, rather than by many designers and architects, so the whole church is like a magnificent symphony. It's a pity that we can't take pictures in it, and we can't tell you how wonderful it is in it with pictures. The middle arc forms the perfect echo wall. You can try it! It takes some physical strength to climb to the top. After all, it has been a landmark of London for many years.