Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Lake Peipus and Russia. The territory of Estonia consists of the mainland and of 2,222 islands on the eastern coast of the Baltic Sea, covering a total area of 45,227 km², and is influenced by a humid continental climate. Tallinn, the capital of Estonia, and Tartu are the largest cities and urban areas in the country. Other notable cities include Narva, Pärnu, Kohtla-Järve and Viljandi. The official language of the country, Estonian, is the second-most-spoken Finnic language.
The territory of Estonia has been inhabited since at least 9,000 BC. Ancient Estonians became some of the last European pagans to adopt Christianity following the Livonian Crusade in the 13th century. After centuries of successive rule by Germans, Danes, Swedes, Poles and Russians, a distinct Estonian national identity began to emerge in the 19th and early 20th centuries.