The Answer to sport worldwide is Soccer, but the biggest fan based team in America is The Dallas Cowboys
Fc Porto has the largest fan base in the world
The English club Manchester united has the largest fan base in the world, Real Madrid comes second.
Kumasi Asante Kotoko FC from Ghana has d largest fan base in Africa and one of the largest in the world. Since its a traditional club, it can bost of about 7 million home fan base alone.
Washington Redskins seems to have a large female fan base.