Tunis (Arabic: تونس‎ Tūnis, pronounced [ˈtuːnis]; Amazigh: Tunes, ⵜⵓⵏⴻⵙ) is the capital of Tunisia. It is Tunisia's largest city, with a population of 651,183 as of 2013. The greater metropolitan area holds some 2,300,000 inhabitants.Situated on a large Mediterranean Sea gulf (the Gulf of Tunis), behind the Lake of Tunis and the port of La Goulette (Halq al Wadi), the city extends along the coastal plain and the hills that surround it. At the centre of more modern development (from the colonial era and later) lies the old medina. Beyond this district lie the suburbs of Carthage, La Marsa, and Sidi Bou Said.Just through the Sea Gate (also known as the Bab el Bahr and the Porte de France) begins the modern city, or Ville Nouvelle, transversed by the grand Avenue Habib Bourguiba (often referred to by popular press and travel guides as "the Tunisian Champs-Élysées"), where the colonial-era buildings provide a clear contrast to smaller, older structures. As the capital city of the country, Tunis is the focus of Tunisian political and administrative life; it is also the centre of the country's commercial activity. The expansion of the Tunisian economy in recent decades is reflected in the booming development of the outer city where one can see clearly the social challenges brought about by rapid modernization in Tunisia.