Why it looks like this

When the Mahdist state took Sudan in 1885, it rejected Khartoum and built its own capital at Omdurman on the White Nile's west bank, around the Mahdi's tomb and the great mosque square. The city grew in the Sudanese way — courtyard houses along irregular lanes, quarter by quarter — and its Souq Omdurman became one of the country's largest markets.

After 1898 the British rebuilt Khartoum opposite as a formal grid, but Omdurman kept growing on its own pattern. Today it is the most populous of the three Nile-junction cities, the indigenous half of the capital's map.