Bulgaria
Bulgaria occupies a portion of the eastern Balkan peninsula, bordering five countries—Greece and Turkey to the south, Macedonia and Serbia to the west, and Romania to the north. The land borders have a total length of , and the coastline has a length of . Its total area of ranks it as the world's 105th-largest country. Bulgaria's geographic coordinates are 43° N 25° E. The most notable topographical features are the Danubian Plain, the Balkan Mountains, the Thracian Plain, and the Rhodope Mountains. The southern edge of the Danubian Plain slopes upward into the foothills of the Balkans, while the Danube defines the border with Romania. The Thracian Plain is roughly triangular, beginning southeast of Sofia and broadening as it reaches the Black Sea coast.
International relations of the Great Powers (1814–1919)
The continuing collapse of the Ottoman Empire led to two wars in the Balkans, in 1912 and 1913, which were a prelude to World War I. By 1900 nation states had formed in Bulgaria, Greece, Montenegro and Serbia. Nevertheless, many of their ethnic compatriots lived under the control of the Ottoman Empire. In 1912, these countries formed the Balkan League. There were three main causes of the First Balkan War. The Ottoman Empire was unable to reform itself, govern satisfactorily, or deal with the rising ethnic nationalism of its diverse peoples. Secondly, the Great Powers quarreled among themselves and failed to ensure that the Ottomans would carry out the needed reforms. This led the Balkan states to impose their own solution. Most important, the members of the Balkan League were confident that it could defeat the Turks. Their prediction was accurate, as Constantinople called for terms after six weeks of fighting.