Chicago is the third largest city in the United States. Once a very important heavy industrial city, the city of evil, the seat of the Bulls that our generation loves. But it's all history. Chicago no longer has so many industries. Now the air is fresh and you enjoy walking around Lake Michigan. Some people say that :"falling in love with Chicago is like falling in love with a woman with a broken nose. Although there is something unsatisfactory, it can not extricate itself. " Travellers to Chicago should bring more clothes to suit the climate. If you happen to encounter a biting wind from Lake Michigan at the intersection in January, you can appreciate the weight of the nickname.