Its hard to believe more cities are not doing this. Pittsburgh has three professional sports teams. The Steelers play in the National Football League (NFL), the Pirates play in Major League Baseball (MLB) and the Penguins play in the National Hockey League (NHL). All three teams share the same color scheme of yellow and black, which represent the colors on Pittsburgh’s flag. There are other major sports teams whose colors represent their city's flag, such as the New York Mets, but Pittsburgh happens to be the only city where all of its major sports teams have adopted their flag's colors.