In this swampy land of rivers, opportunities for agriculture were limited. Consequently, trade and cities start to flourish at an early stage. From the late Middle Ages onwards, the Low Countries develop a modern and innovative economy which turns the region into an important hub of world trade. They are not afraid of engaging in violence and exploitation in this process. Since that time, the area has been attracting large numbers of migrants who help to keep up the economy. The Netherlands has thus been a prosperous country for centuries, although this prosperity is not divided equally. The economy benefits from open borders; however, its extreme dependence on such open borders renders it vulnerable.