[IMAGE1] To set foot on African soil is to be immediately aware of the land. The very earth under your feet, rusty red-brown or sandy-gold, the huge horizons, the sheer distance between places, all proclaim difference. After harmonious, cultivated Europe, there is a sense of primal rawness. The sheer vastness of the continent (which could swallow all of Europe, North America and India with barely a hiccup) imposes itself at every turn. Its immense age stares at you from every wrinkled kopje and parched savannah, yet at times one has the feeling of walking in the first dawn of the world.

Delusion this may be, but science does little to diminish the sensation. Viewed from orbiting spacecraft, Africa curls like a great swollen-headed foetus across the Equator. Once the great central plateau of Gondwanaland, before the other continents drifted away, it lies bathed in the warm tropic winds, the cradle of mankind, at once strangely infantile and unimaginably old.

For all its preposterous size - 8000km in length and 4600km at its widest - it is a single slab or "shield", a continuous plateau (or succession of plateaux) rising progressively from north-west to south-east, to end in steep escarpments dominating narrow coastal plains. To these raised edges of the old continent, volcanic activity has added magnificent mountains. The line ripples down from Namibia to the Cape, skirts the coast running eastwards and up - the Drakensberg and Chimanimani ranges, the Mountains of the Moon, Mounts Kenya and Kilimanjaro (Africa's highest at 5895m) - to the Great Rift Valley, a chasm 50km wide running 5500km from Mozambique into Jordan, scattering along the way the surreal landscapes of Ethiopia and the immense Serengeti plains, the probable birthplace of mankind.

Spectacular (and photogenic) these may be, but they say little about the countless intimate ways in which landscape has shaped human life. Western civilisation itself owes much to the network of rifts, tiltings and plains of the catchment that created the Nile, whose annual floodings gave rise to the sciences and arts of the ancient Egyptians. European settlement of the South and East was made possible only by the high altitudes that render the tropical and subtropical latitudes not simply bearable but near-idyllic. Warm winds rising from the Indian Ocean to cross these highlands precipitated another blessing, convectional rainfall, in quantities ideal for such typical settler crops as tobacco or coffee. In the arid north the immense sand oceans of the Sahara (once, in another geological era, themselves under water) shaped the lives of Berber and Bedouin; in the south-west the near-desert conditions of the Kalahari fostered and preserved the most ancient human culture of all, that of the San hunter-gatherers. Now geology, in the form of diamonds under their ancestral lands, threatens them with expulsion and cultural annihilation. Altogether Africa's minerals have proved a mixed blessing. Into the ancient kingdom of Monomatapa gold first drew traders, then slavers, missionaries and finally armed settlers. The pattern was repeated across the whole continent.

But it is in the Bantu territories of sub-Saharan Africa that one best sees how intimately the land is tied to culture and religion. Here spiritual life involves constant communication with the ancestors, whose home is in the soil. Moving the site of a village to better pastures can provoke a terrible debate with the dead, who cannot uproot themselves from their place of burial. Earth, mankind and the spirit world are indivisible. When Zimbabwe Government officials tried to eject local communities from the Matobo hills to make way for a tourist enterprise, the potential ecological damage was carefully explained to them: "If you move the people off the land, the water from the rocks will cease to flow. The water is the gift of the rocks to the people."

Such is the extraordinary oneness of this land and the cultures it has shaped.