1. Spray paint was invented in Chicago in 1949.
2. Chicago River is the only river in the world that flows backward.
3. Chicago is home to Lincoln Park Zoo, one of the world's last free zoos.
4. The Art Institute of Chicago holds the largest collection of Impressionist paintings outside the Louvre in Paris.
5. The first blood bank in the United States was created in Chicago in 1937.
6. Chicago's Western Avenue is the world's longest continuous street, at 23.5 miles.
7. Chicago is home to the world's largest free outdoor food festival, the Taste of Chicago.
8. An average of 35 million visitors flock to Chicago each year.
9. The Chicago Public Library was created directly from the ashes of the great Chicago Fire in 1871.
10. Chicago was technically the birthplace of soap operas.
11. Shedd Aquarium is home to the oldest aquatic animal in a public aquarium in the world, an Australian lungfish named Granddad, who is at least 85 years old.
12. The first Playboy Mansion was in Chicago.
13. And Hugh Hefner started the publication of Playboy in Chicago in 1953.
14. The zipper was invented in Chicago in 1851.
15. The Ferris wheel was also invented in Chicago in 1893.
16. Ebony magazine began publication in Chicago in 1945.
17. The Twinkie was invented in Chicago in 1930.
18. Chicago resident Jane Addams, founder of the Hull House, was the first American woman to win the Nobel Peace Prize in 1931.
19. The movie I-Robot was filmed in Chicago.
20. And Gotham City from Batman was based largely off of Chicago.
21. In fact, Gotham City license plates were designed to look like Illinois plates so that they would be consistent with other plates while filming car-chase scenes in the city.
22. The first all-color TV station made its debut in Chicago in 1956.
23. The vacuum cleaner was invented in Chicago in 1868.
24. Chicago invented the deep-dish pizza.
25. And Chicago is the home of the first black president of the United States, Barack Obama.
26. Four states are visible from the top of the Willis Tower (Indiana, Illinois, Michigan, and Wisconsin).
27. The first televised U.S. presidential debate was broadcast from Chicago's CBS Studios on Sept. 26, 1960, between John F. Kennedy and Richard Nixon.
28. Chicago is home to 552 parks.
29. Chicago has 15 miles of bathing beaches.
30. Chicago is home to 11 Fortune 500 companies.
31. Historic Route 66 began in Chicago.
32. Walt Disney was born in Chicago.
33. In 1885, Chicago became home to the first skyscraper, the Home Insurance Building, which was originally nine stories tall.
34. In 1779, Jean Baptiste Point du Sable, a Haitian immigrant, built the first permanent settlement in what would be Chicago near the present Michigan Avenue Bridge on the north bank.
35. The four stars on the Chicago flag represent Fort Dearborn, the Chicago fire, the World's Columbian Exposition, and the Century of Progress Exposition.
36. Nancy Green, the first spokesperson for Aunt Jemima syrup, was introduced to the public for the first time in Chicago.
37. The first animal purchased for the Lincoln Park Zoo was a bear cub, bought for $10 in 1874.
38. Pabst Blue Ribbon beer (PBR) was first introduced during the 1893 Colombian Exposition, also known as the 1893 World's Fair, which was held in Chicago.
39. Cracker Jacks were also introduced during the 1893 Chicago fair.
40. In 1895, the first automobile race ever seen in the United States was held in Chicago.
41. The first Rotary Club in America was founded in Chicago.
42. Chicago is known as the home of baton twirling. This is because the first baton-twirling contest was held as part of the Chicagoland Music Festival in 1935.
43. The Wrigley Building was the first air-conditioned office building.
44. The first McDonald's franchise restaurant, owned by Ray Kroc, opened in the Chicago suburb of Des Plaines in 1955.
45. The longest MLB game to ever be played was in 1984 at Comiskey Park in Chicago. Chicago White Sox defeated the Milwaukee Brewers after 25 innings.
46. Chicago inventor Martin Cooper invented the first cell phone.
47. In 1924, the first gay rights group in the U.S. was created in Chicago.
48. The first form of softball was invented in Chicago.
49. In 1893, the first open heart surgery in the United States was performed in Chicago.
50. In 1960, the first Playboy Club to feature bunnies opened in Chicago.