The Drömling is a sparsely populated depression on the border of Lower Saxony and Saxony-Anhalt in Germany with an area of about 340 square kilometres (130 sq mi). The larger part belonging to Saxony-Anhalt in the east has been a nature park since 1990. The former swampland was transformed by drainaged from a natural into a cultural landscape in the 18th century under the direction of Frederick the Great of Prussia . Today the depression, with its waterways, the Mittelland Canal and the rivers Aller and Ohre is a refuge for rare or endangered species of animal and plant. Most of the area is now made up of nature reserves and protected areas.