The longest road in spreads across 10 countries and stretches a staggering 6,000 miles. Trans- Highway 4, also known as TAH 4, or The Cairo-Cape Town Highway, is a part of the huge transcontinental road network being developed.

The route, developed by the United Nations Economic Commission for (UNECA), the African Development Bank (AfDB), and the African Union, and goes all the way from the north to the south of the vast continent. On the way, it passes through Addis Ababa, Ethiopia, then Sudan, Ethiopia, Kenya, Tanzania, Zambia, Zimbabwe, and Botswana, and finishing up in South Africa.

The idea of the route goes back at least as far as the times of British Imperial rule, and a rail link aimed to connect Cape Town in Cairo - both of which had been controlled by Britain - was started but not completed before the colonialists were kicked out, as per the ' website.

The plan was later revived as part of the Trans-African Highway, a transcontinental road network developed by the UNECA, the ADB, and the African Union, and named the Cairo-Cape Town Highway.

Though it largely follows roads as the original Cape to Cairo Road, there are some deviations.

It begins in the north of the continent at the port of Alexandria on the Mediterranean Sea before passing through the Egyptian capital as it heads southward.

Works on the highway continue though is said to be almost complete. Works on the Trans-African Highway Network are ongoing.

The network is made up of nine highways, including TAH 4, and covers 35,221 miles in total, reports suggest.

It was designed to facilitate trade between African states, as well as bringing down the cost of transportation costs, as well as improving links between landlocked countries and coastal regions.

Leaders hope it will also revitalise small and medium-sized businesses, reduce the price of goods, and

This will hopefully be achieved in part through its road-based trade corridors.