Lithuania is a country in northeastern Europe. Located by the Baltic Sea, it shares land borders with Latvia, Belarus, Poland and the Russian exclave of Kaliningrad. Lithuania’s political and economic capital is Vilnius, but the city of Klaipeda, which is home to the main ice-free port on the eastern coast of the Baltic Sea, is also of strategic importance to the country. Lithuania is mostly flat, with several short rivers and multiple lakes. Its main river is the Neman, which begins in Belarus and flows through Lithuania before reaching the Baltic Sea. A third of Lithuania’s territory consists of woodlands, while the fertile lands in the country’s center represent the core of Lithuania’s agricultural sector. Lithuania rose to prominence in the 14th century as the Grand Duchy of Lithuania, which extended over parts of modern-day Belarus, Ukraine, Poland and Russia. In the late 16th century, Lithuania and Poland formed the Polish-Lithuanian Commonwealth, becoming a major European power. But despite its occasional might, Lithuania has often faced threats from its powerful neighbors, which over the centuries have included Germany, Austria, Russia and Sweden. By the late 19th century, imperial Russia had absorbed most of Lithuania’s territory. While Lithuania briefly obtained independence in 1918, the Soviet Union annexed the country after World War II. Lithuania was a Soviet republic until 1990, when it became independent once more. Since then, Lithuania has joined NATO, the European Union, the Schengen agreement and the eurozone. Lithuania’s main geopolitical concern in Russia. The country’s fear of potential Russian aggression increased after Moscow’s military intervention in Ukraine in 2014. In recent years, the country has increased its military expenditures and sought to reduce its dependence on Russian energy. In 2014, for example, it opened an LNG terminal in Klaipeda. Despite Vilnius' fears, Russia remains Lithuania’s main trade partner. Lithuania’s main geopolitical challenge is thus to cooperate with its neighbors in the Baltic region, the broader European Union and NATO to secure political, economic and military protection against potential foreign aggression.