Baku is the capital and largest city of Azerbaijan. Located on the southern shore of the Absheron Peninsula along the Bay of Baku, it serves as the nation's primate city and its only metropolis. It is also recognized as the largest city in the Caucasus region and the largest city on the Caspian Sea.
The city is situated 28 metres (92 ft) below sea level, making it the lowest-lying national capital in the world and the largest city globally at that elevation. Baku has an urban population of over two million people, accounting for approximately 25% of Azerbaijan's total inhabitants within its metropolitan area.