Zinder (which is locally called Damagaram) is the second largest city in Niger, with a population of 170,574 (2001 census)[1] by 2005 was estimated to be over 200,000. It is situated 861 km (535 mi) east of the capital Niamey and 240 km (150 mi) north of the Nigerian city of Kano. Zinder rose from a small Hausa village to an important centre of the Trans-Saharan trade with the founding of the Sultanate of Damagaram in 1736 by Kanouri aristocrats. The large fortress of the southeast central city (Birini) was built shortly thereafter, and became a major hub for trade south through Kano and east to Bornu. The Tuareg encampments and trade houses of the Hausa town (Zengou) expanded with this trade. The French conquered the city in 1899, and placed the capital of the new Niger Military Territory there in 1911. In 1926, following fears of Hausa revolts and improving relations with the Djerma of the west, the capital was transferred back to the village of Niamey. In 2003, telecommunications company Celtel arrived in Zinder, building a mobile phone tower and selling prepaid phone cards to residents. This arrival of the mobile phone drastically changed the predominant modes of communication in the city, allowing traders to have a faster and more affordable means of communicating with buyers and sellers. This is an example of how cellular towers in the developing world have begun to transform the market. Today, Zinder comprises three main areas. Birni, the old town, is home to Zinder Great Mosque and the Zinder Sultan's Palace, as well as a museum. Zengou or Zango, the old Hausa settlement, is known for its vernacular architecture. Sabon Gari (the new town), between Birni and Zengou, is the commercial centre, known for its large market. The city now sprawls to the north and west, extending to the Karkada section, in the north. Other neighbourhoods include Garin Mallam and Gawon Kollia. The city has many distinctive granite rocks which can result in standing water during the rainy season, though the city has a long history of water shortages. Recently water was piped by a Chinese-owned company from the north to provide water to most of the city, however, this problem is likely to continue due to expected population growth. In November 2011, Niger Republic's first oil refinery was commissioned in Zinder. Zinder Airport (code: ZND) is located a few miles to the southwest of the town.