Rotterdam is the second city of Holland / The Netherlands. To be honest it is also the most ugly city of Holland and the atmosphere is not the best. However it has the biggest port of Europe and one of the biggest in the world and therefore it is for business a good place to be or to go.
Rotterdam has the football club Feyenoord, which was famous in the past, but currently is a moderate club in Holland and in Europe they are not as they have financial problems. Ajax from Amsterdam however does much better and is in better condition.
As they always say: the money is earned in Rotterdam and spend in Amsterdam!