- Poland (Wikipedia)
Poland (Polish: Polska [ˈpɔlska]), officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, while its longest river is the Vistula. Poland has a temperate transitional climate and is the fifth-most populous member state of the European Union, with its sixteen voivodeships having a total population of over 38 million and covering a combined area of 312,696 km2 (120,733 sq mi). It is bordered by Lithuania and Russia to the northeast, Belarus and Ukraine to the east, Slovakia and the Czech Republic to the south, and Germany to the west. The nation’s capital and largest metropolis is Warsaw. Other major cities include Kraków, Wrocław, Łódź, Poznań, and Gdańsk.
- Drainage basin (Wikipedia)
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern.