This is Philadelphia landmark, Philadelphia City is very small, two hundred years ago the planned grid road is still the most important texture of the city today. Thus, the City Hall, located in the center of the city, can be easily seen from all angles. At first, Philadelphia stipulated that the height of the building should not be higher than that of the bronze statue. Later, due to the need of municipal development, it had to deceive itself that the old Penn "invisible" on the back of the bronze statue could be built high-rise buildings, so today the east side of the building still maintains its primitive style, while the west side has a series of skyscrapers. When it was built in 1901, the 167m high city hall was the tallest building in the world at that time. Today, this huge city hall is still one of the tallest and largest masonry structures in the world. I went to its feet and found that it was much bigger than the photo. I couldn't see the bronze statue on the top. Closer to it, the stone walls of the building are old and somewhat dark, carved with complex patterns and figures. It is still the office space of the Philadelphia government, open to the outside world, and free guides from Monday to Friday can visit the conference room and introduce the political system of the United States. Through the city hall, it's an open square. The fountain pool became a playground for children.