Short facts

The colors in the Tanzanian flag symbolizes the grass, the sun, the people and the water.
The name Tanzania is composed of the names of the mainland (Tanganyika) and the islands of Zanzibar. The territories have been controlled by foreigners beginning with the Portuguese, then the Arabs, Germans and Britons. In October 1964 British control/occupation ended and the United Republic of Tanzania was declared.

Capital Dodoma  
Largest town Dar es Salaam  
Area (incl. Zanzibar) 945 203 km²         
Population 52 millions (2014)  
Official languages KiSwahili and English  
Current Tanzania shilling TZS  
Union Day April 26 The unification of Tanganyika and the People's Republic of Zanzibar in 1964
Independence day December 9 Celebrating the end of British rule in 1961

A comprehensive description of Tanzania can be found in Bradts travel guide to the country, written by Philip Briggs who has spent many years traveling in Africa.
Here are his own words about Tanzania on the occasion of the sixth edition of the book (September 2009):

It would be easy to reduce an introduction to Tanzania to a list of facts and figures. This vast East African country really is a statistician's dream: within its borders lie Africa's highest and fifth highest mountain, the world's largest intact volcanic caldera, Africa's most famous national park, and the world's largest game reserve, as well as portions of the three most expansive lakes on the continent, one of which is the second-largest freshwater body in the world, another the second-deepest.
When it comes to wildlife, Tanzania is practically withour peer.  An unprecedented 25% of the country is protected in national parks and other conservation areas. Together, these support an estimated 20% of Africa's large mammal population, and one of them plays host to the singular spectacle of an annual migration of some two million wildebeest, zebra and gazelle.  Furthermore, Tanzania has recently overtaken Kenya as boasting Africa's second-largest bird checklist (after the Democratic Republic of Congo) with more than 1,130 bird species recorded, and new endemics being discovered all the time. And as if that were not enough, the three great lakes that lie along Tanzania's borders vie with each other for the honour of harbouring the world's greatest diversity of fish species.

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Travel isn't simply about ticking off the sights. When you spend a long time in a country, your feeelings towards it are determind more than anything by the mood created by its inhabitants. I have no hesitation in saying that, on this level, my affection for Tanzania is greater than for any other African country I have visited. It is an oasis of peace and egalitarian values in a continent stoked up with political and  tribal tensions, and its social mood embodies all that I respect in African culture. As a generalisation, I've always found Tanzanians to be polite and courteous, yet also warm and sincere, both among themselves and in their dealings with foreigners.
The one thing I can say with near certainty is that you will enjoy Tanzania. Wether you decide to stick to the conventional tourist circuit, opt to carry a dusty backpack around the southern highlands or charter a plane to go chimp tracking in the rainforests of Mahale, you'll find that Tanzania is a wonderful country.
 

Philip Briggs