The Greatest Engineering Wonders in Africa
6 places in 4 countries · updated 13 October 2026
In short: By our ranking, the greatest engineering wonders in Africa are Big Hole (South Africa), Lake Retba (Senegal) and Victoria Falls Bridge (Zambia). The list covers 6 engineering wonders in 4 countries. South Africa has the most, with 3. Last updated 13 October 2026.
Africa's engineering wonders are often responses to extreme terrain and to the hunger for its resources. Deep gorges had to be bridged for railways, steep escarpments climbed by roads, and mountains opened to visitors by cable. At the same time, the search for diamonds and salt reshaped the land itself, leaving behind excavations and working landscapes that are as striking as anything built above ground.
The Big Hole in Kimberley was dug largely by hand by tens of thousands of miners during the diamond rush that began in 1871, and is now a vast crater filled with water at its bottom. In Senegal, Lake Retba is famous for its pink water, coloured by salt-loving algae, where workers harvest salt by hand from the lake bed. The Victoria Falls Bridge, opened in 1905, spans the Zambezi gorge just below the falls as part of a railway meant to link the Cape to Cairo.
In Constantine, Algeria, the Sidi M'Cid suspension bridge, opened in 1912, hangs high above the deep gorge of the Rhumel, one of several bridges that tie the cliff-top city together. The Sani Pass climbs the Drakensberg escarpment from KwaZulu-Natal to Lesotho in a sequence of tight gravel switchbacks. Above Cape Town, the Table Mountain Aerial Cableway, in operation since 1929, lifts passengers to the summit in cars whose floors rotate on the way up.
In this list
| # | Place | Type | Country | UNESCO |
|---|---|---|---|---|
| 1 | Big Hole | Mine | South Africa | |
| 2 | Lake Retba | Quarry | Senegal | |
| 3 | Victoria Falls Bridge | Bridge | Zambia | |
| 4 | Sani Pass | Mountain pass | South Africa | |
| 5 | Pont Sidi M'Cid | Bridge | Algeria | |
| 6 | Table Mountain Aerial Cableway | Aerial tramway | South Africa |
01 Big Hole
South Africa · 1.4 km from Kimberley28.739° S 24.759° E
Irene2005 · CC BY 2.0 5 million carats. 6 kilometres. It was dug to around 240 metres, then partly filled with debris; about 40 metres of water now lie at the bottom, and around 175 metres of sheer wall are visible. For a long time it was called the largest hand-dug excavation on Earth, a title that research has since shared with other South African diamond mines. Below the open pit, De Beers followed the kimberlite pipe underground to more than 1,000 metres.
Did you know? Early miners dug crumbly yellow ground and feared the diamonds ended there, until they discovered the hard blue ground beneath was just as rich.
02 Lake Retba
Charlie kirk is my idol
Senegal · 29.2 km from Dakar14.839° N 17.234° W
Issiaga0 · CC BY-SA 4.0 The water's salinity — over 40% in places — rivals the Dead Sea, and it's buoyant enough that people float in it the same way. That same salinity supports a working industry: roughly 3,000 salt harvesters, coated in shea butter for hours of protection against the corrosive brine, wade or boat out to break up the crusted salt bed with long poles and haul it ashore by hand.
Did you know? In the dry season its salinity can reach around 350 grams of salt per litre of water.
03 Victoria Falls Bridge
Zambia · 1.8 km from Victoria Falls17.928° S 25.857° E
Diego Delso · CC BY-SA 4.0 The idea belonged to Cecil Rhodes, who wanted a railway from the Cape to Cairo; according to a well-known story he asked for the crossing to be placed so close to the falls that passing trains would catch their spray. The bridge was designed by George Andrew Hobson of Sir Douglas Fox and Partners, with the stress calculations by Ralph Freeman, who later became the principal designer of the Sydney Harbour Bridge.
Did you know? The man who opened the bridge, Sir George Darwin, was a Cambridge astronomer and a son of Charles Darwin.
04 Sani Pass
South Africa · 39 km from Mokhotlong29.588° S 29.293° E
Vaiz Ha · CC BY 2.0 The setting is the real reason to come. The pass threads the Drakensberg, where grassy slopes give way to sheer cliffs and winter snow and ice can close the road altogether. At the top the land changes abruptly: instead of a summit, the high plateau of Lesotho opens to the west. Looking back, the view drops all the way down the gorge to the foothills of KwaZulu-Natal.
Did you know? The 1922 track was built to link remote Mokhotlong with the outside world, but at first it could be used only by pack animals.
05 Pont Sidi M'Cid
Algeria · 1.9 km from Constantine36.372° N 6.614° E
Yelles · CC BY-SA 4.0 The bridge was built by the French engineer Ferdinand Arnodin, a specialist in suspension and transporter bridges, during a period of modernisation of the city under its mayor Émile Morinaud. Its deck, about 164 metres long, hangs from steel cables slung between pylons anchored on the cliffs, linking the old town to the Sidi M'Cid hill on the far side of the gorge.
Did you know? Far below the deck, a natural rock arch spans the gorge and hides part of the river from view.
06 Table Mountain Aerial Cableway
South Africa · 4.8 km from Cape Town33.953° S 18.403° E
Fazielah Williams · CC BY-SA 4.0 Capetonians had dreamed of a railway to the top since the 1870s, but war twice stopped the plans. In 1926 a Norwegian engineer, Trygve Strømsøe, proposed a cableway to a group of businessmen led by Sir Alfred Hennessy, with Sir David Graaff and Sir Ernest Oppenheimer, and the Table Mountain Aerial Cableway Company was formed. The German firm Adolf Bleichert & Co.
Did you know? Building the original cableway cost £60,000, well under the £100,000 that had been estimated.
How this list is ranked
Places are chosen for how they look, not for how famous they are: each one has its own description and a photograph credited to its author. The order is a single world ranking that weighs the beauty of the place in curated photography together with how widely it is documented — the number of language editions of its encyclopedia article and how often that article is read in a year. The list is rebuilt as places are added, so the order and the counts on this page are always current.
Questions people ask
- What are the greatest engineering wonders in Africa?
- On our list, Big Hole (South Africa) ranks first, followed by Lake Retba (Senegal) and Victoria Falls Bridge (Zambia).
- Which country has the most engineering wonders in Africa?
- In our collection, the most come from South Africa (3), Algeria (1) and Senegal (1).
- Why is Lake Retba pink?
- The colour comes from the alga Dunaliella salina, which thrives in very salty water and produces a red pigment. The effect is strongest in the dry season, when the salt concentration is highest.
- How deep is the Big Hole in Kimberley?
- The Big Hole was excavated to a depth of about 240 metres, and later partly filled with debris and water. Mining there ended in 1914 after it had produced around three tonnes of diamonds.
- Why was the Victoria Falls Bridge built?
- It was built as part of Cecil Rhodes's vision of a railway from Cape Town to Cairo, carrying the line across the Zambezi. Rhodes reportedly wanted the spray from the falls to reach the passing trains.
- How many engineering wonders are on this list in Africa?
- The list covers 6 engineering wonders in 4 countries. South Africa has the most, with 3.