Baku ), sometimes spelled as Baki or Bakou, is the capital, largest city, and largest port of Azerbaijan and the Caucasus region. It is located on the southern shore of the Absheron Peninsula, that projects into the Caspian Sea. The city consists of two principal parts: the downtown and the old Inner City (21.5 ha). Baku's urban population at the beginning of 2009 was estimated at just over two million people.Baku is divided into eleven administrative districts (raions) and 48 townships. Among these are the townships on islands in the Baku Bay and the town of Oil Rocks built on stilts in the Caspian Sea, 60 km away from Baku. The Inner City of Baku along with the Shirvanshah's Palace and Maiden Tower were inscribed as a UNESCO World Heritage Site in 2000. According to the Lonely Planet's ranking Baku is also amongst the world's top ten destinations for urban nightlife.The city also serves as the main economic hub of Azerbaijan. Many sizeable Azerbaijani institutions have their headquarters there, including SOCAR, one of the world's top 100 companies. The Baku International Sea Trade Port, sheltered by the islands of the Baku Archipelago to the east and the Absheron Peninsula to the north, is capable of handling two million tons of general and dry bulk cargoes per year.