Thuringia, officially the Free State of Thuringia, is one of Germany's 16 states with 2.1 million people, its 12th-largest by population, and with 16,171 square kilometers, its 11th-largest in area. Erfurt is the capital and largest city. Other cities include Jena, Gera and Weimar. Thuringia is bordered by Bavaria, Hesse, Lower Saxony, Saxony-Anhalt, and Saxony. It has been known as "the green heart of Germany" from the late 19th century due to its broad, dense forest.