Netherlands, Serbian and South Sudanese are the tallest people actually in average (it may changed, don't forget that American where the tallest at one time)
the difference is that South Sudanese are thinner and have longer legs and arms giving them a very tall appearance. And even though they are living in very bad conditions, they still keep their tall stature. It is the same with Somalian who remains quite tall (but not as much as European people)
however the average in northern europe is absolutely not 6ft (except maybe in Netherlands, but even there is it rather something between 180 and 182)
there is some stereotypes coming mainly from northern european proudness who wants to make us believe that all southern european are short people. In reality, if you look at national average, it is quite minimal. Maybe one inch or two at best
