Azerbaijan, officially the Republic of Azerbaijan , is a country in the Transcaucasian region, situated at the crossroads of Southwest Asia and Southeastern Europe.Baku, is the capital and largest city of Azerbaijan, as well as the largest city on the Caspian Sea and of the Caucasus region. Baku is located 28 metres (92 ft) below sea level, which makes it the lowest lying national capital in the world and also the largest city in the world located below sea level.Ganjais Azerbaijan's second largest city with a population close to 820,000. TheNakhchivan Autonomous Republicis a landlocked exclave of the Republic of Azerbaijan. The region covers 5,500 km2 with a population of 410,000, bordering Armenia (length of frontier 221 km) to the east and north, Iran (179 km) to the south and west, and Turkey (only 15 km) to the northwest. TheKura Riverstarts in northeastern Turkey, it flows through Turkey to Georgia, then to Azerbaijan, where it receives the TheArasas a right tributary, and enters the Caspian Sea. TheMingachevir reservoiris a large reservoir in northwestern Azerbaijan. TheAras or Araxesis a river in and along the countries of Turkey, Armenia, Azerbaijan, and Iran.The Caucasusis a region at the border of Europe and Asia, situated between the Black and the Caspian seas, it is home to the Caucasus Mountains.