Major League Baseball (MLB) - the most important and oldest American baseball league. There are 30 teams participating in it. It consists of two leagues: National League and American League, each divided into three divisions. ¹⁾

Professional baseball has it roots in the first professional team in 1869, the Cincinnati Red Stockings. With eight professional clubs, the National League was founded in 1876. Then, in 1901, another baseball league was created - the American League. The first American League had eight teams in it. ²⁾