Lithuania is a north-eastern European country, the largest and southernmost of the three Baltic states. In the 14th-16th centuries, Lithuania was a powerful empire that ruled much of Eastern Europe before becoming part of the Polish-Lithuanian Confederation for the following two centuries. There are no high mountains in Lithuania, where the landscape is characterized by flowering meadows, dense forests and fertile cereal fields. The country is especially water-rich, with over 3000 lakes, mainly in the north-east. It is also drained by several rivers, the longest of which is the Nemunas. Lithuania has two terrestrial ecoregions: the Central European Mixed Forest and the Sarmatian Mixed Forest. The country is home to 5 national parks, 30 regional parks, 402 nature reserves and 668 state-protected natural heritage objects. Wildlife populations have recovered since hunting was restricted, and forests have begun to be replanted, having tripled in size since the low point. There are now around 250 000 large wild animals in Lithuania, meaning there are 5 wild animals for every square kilometer. The most common large game animal in all parts of Lithuania is the Roe Deer, followed by the Wild Boar, the deer, the Fallow Deer and the largest, the moose. The fox is the most common of the Lithuanian predators, but wolves are the most mythologically significant, with only 800 individuals living in Lithuania. Lynxes are even rarer, but there may be as many as 200 000 rabbits in Lithuanian forests. The White Stork is the national bird of Lithuania, with the largest stork population in Europe.