The Chicago Marathon, officially called the Bank of America Chicago Marathon, is the pinnacle event for novice to elite runners. Participants from over 50 states and more than 100 various countries pack themselves into Grant Park to take part in both the marathon event and the spectacular celebration. Chicago, a city like no other, is a big city with an even bigger heart. One of the most beloved marathons around the world, people from around the globe compete to race around the downtown center and to get a glimpse of Lake Michigan and the city skyline. Considered a flat and fast course; it is one of the big-5 marathons that comprise the Wold Marathon Majors series. Starting with just 4,200 runners when it began in 1977, it has grown to over 45,000 in just a little over three decades. The Midwestern spectators are something that makes this marathon amazing, as is the excitement in the air of the city, which comes alive to cheer marathoners to the finish line.

Source: World's Marathons.