Old City or Inner City is the historical core of Baku, the capital of Azerbaijan. The Old City is the most ancient part of Baku, which is surrounded by walls. In 2007, the Old City had a population of about 3,000 people. In December 2000, the Old City of Baku, including the Palace of the Shirvanshahs and Maiden Tower, became the first location in Azerbaijan to be classified as a UNESCO World Heritage Site.

Baku is the capital and largest city of Azerbaijan, as well as the largest city on the Caspian Sea and in the Caucasus region. Baku is 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 below sea level. Baku lies on the southern shore of the Absheron Peninsula, on the Bay of Baku. Baku's urban population was estimated at two million people as of 2009. Baku is the primate city of Azerbaijan—it is the sole metropolis in the country, and about 25% of all inhabitants of the country live in Baku's metropolitan area.