Africa

Africa is the world's second-largest continent and the hottest. Almost a giant plateau astride the equator, it is crossed by both the Prime Meridian and the Equator, making it the most centrally located continent. It was long called the "Dark Continent" because its interior stayed unknown to outsiders. Today Africa is known for the Sahara, the Nile, spectacular wildlife and enormous mineral wealth.

Africa is essentially a high plateau continent with a remarkably smooth, short coastline for its size. Its key features:

• The Great Rift Valley, a vast trench running from the south, past a chain of long lakes, up to the Red Sea.
• The highest peak, Mount Kilimanjaro (5895 m), snow-capped though near the equator.
• The Sahara in the north, the largest hot desert in the world, and the Kalahari in the south.
• Great rivers: the Nile (the world's longest, fed by Lake Victoria, Africa's largest lake), the Congo (Zaire), the Niger and the Zambezi. The Zambezi plunges over the Victoria Falls.

It is separated from Europe by the Mediterranean Sea and from Asia by the Red Sea and the Suez Canal.

The Congo Basin is the vast depression of Central Africa drained by the Congo River and its tributaries. It is the world's second-largest river basin after the Amazon. The countries within it include the Democratic Republic of Congo, the Republic of Congo, the Central African Republic, Gabon, Equatorial Guinea, Angola and Cameroon. Cameroon counts because its southeast drains into the Congo system. Three nearby countries are common traps:

• Nigeria: drains through the Niger River, not the Congo.
• Uganda: lies in the Nile system, outside the Congo watershed.
• South Sudan: also lies in the Nile system, not the Congo Basin.

West Africa has its own lakes, separate from the Rift Valley chain:

• Lake Faguibine (Mali): a lake fed by the seasonal flooding of the Niger River. Reduced flooding and desertification have largely dried it up. Much of its bed has turned into desert.
• Lake Volta (Ghana): a huge man-made lake formed by the Akosombo Dam on the Volta River.
• Lake Oguta (Nigeria): a natural freshwater lake in the floodplain of the Niger.

Because the equator runs through its middle, Africa's climate and vegetation form near-symmetrical belts north and south of the equator:

• Equatorial climate at the centre: hot and wet, with dense tropical rainforest.
• Savanna (Sudan type): tropical grassland with warm summers and a dry season, famous for big game.
• Hot desert climate (Sahara, Kalahari): extreme heat and almost no rain, with only scrub vegetation.
• Mediterranean climate on the northern and southern coasts: mild wet winters and warm dry summers.

The hottest temperature ever recorded was at Al-Aziziyah (Libya).

Africa is extraordinarily rich in minerals. It produces about 95% of the world's diamonds and more than half its gold. South Africa's Johannesburg is known as the "Golden City". Africa also holds large reserves of cobalt, copper, chromium, bauxite and uranium. Petroleum is found in Nigeria, Libya and Angola.

Its farms supply the world with cocoa (Ghana, Nigeria), coffee, palm oil, dates and cloves (Zanzibar and Pemba). Only about a tenth of Africa's land is cultivable.

Africa has 54 countries and great human diversity. Swahili is widely understood, alongside English, Arabic, French and Portuguese. Nigeria has the largest population. Algeria is the largest country by area.

Notable countries include Egypt, where the Suez Canal links the Mediterranean and Red Sea. The Democratic Republic of Congo is called the "Land of Forests". South Africa is the "country of diamond and gold", with capitals at Pretoria and Cape Town.