Dar es Salaam formerly Mzizima, is the largest city in Tanzania and is located on a bay of the Indian Ocean. It has a population estimated at around 2,500,000, and is the country's richest city and an important economic centre. Despite losing its official status as capital city to Dodoma in the mid-1970s, Dar es Salaam remains the centre of the permanent central government bureaucracy. Major industries produce food, beverages, oil, textiles, clothing, shoes, cement, aluminum products, and pharmaceuticals. Dar-es-Salaam is Tanzania's main port and exports include cotton, sisal, coffee, diamonds and hides.

In 1859, Albert Roscher of Hamburg was the first European to land in Mzizima ("healthy town"). In 1866 Sultan Seyyid Majid of Zanzibar gave it its present name, an Arabic phrase meaning Haven of Peace. Following Majid’s death in 1870, Dar es Salaam fell into decline but was revived when the German East Africa Company established a trading station there in 1887 overthrowing the Arabic rulers and colonizing the East Africa coast. They built an administrative center to oversee local issues in German East Africa and a commercial center to direct the development of the Central Railway Line. Its growth was made easy by its role as the administrative and commercial centre of German East Africa. In 1891 it became the capital of German East Africa.

During World War I, German East Africa was captured by the British and since then it was referred to as Tanganyika. After World War II, Dar es Salaam experienced a period of rapid growth including the formation and growth of the Tanganyika African National Union (TANU) which led to Tanganyika attaining its independence in December 1961. Dar es Salaam continued to serve as its capital until provisions were made in 1973 to relocate the capital to Dodoma, a more centrally located city in Tanzania's interior.

German historical influences are still visible in the city. Dar es Salaam is an important city for both business and government. The city is the hub of the Tanzanian transportation system as all of the country's main railways and several highways originate in or near the city. The Dar es Salaam Airport connects the city with other African countries, the Middle East as well as Europe.

There are a variety of museums, including the National Museum, the Village Museum and the Botanical Gardens. There are beaches on the Kigamboni peninsula East of Dar es Salaam and on Kigamboni Island to the North where residents and tourists frequently visit.  

Dar es Salaam is also the educational centre of Tanzania. It is home to the University of Dar es Salaam, the Open University of Tanzania, the Hubert Kairuki Memorial University (HKMU) as well as the International Medical and Technological University (IMTU) among others.  

Reference:

http://en.wikipedia.org/wiki/Dar_es_Salaam
http://www.go2africa.com/tanzania/dar-es-salaam/dar-es-salaam/
http://www.infoplease.com/ce6/world/A0814655.html