Katse Dam

Katse is the centrepiece of the Lesotho Highlands Water Project - a concrete arch wall about 185 metres tall, among Africa's largest of its kind, closing a Maluti valley so that mountain water can run by tunnel toward Johannesburg's thirsty conurbation while spinning Lesotho's turbines en route. The engineering tour is the draw done right: visitors walk galleries inside the wall itself, feeling the mass hum, and the visitor centre lays out the audacity of tunnelling water through mountains. Above ground, the drive in over passes brushing 3,000 metres is one of the country's great roads, and the dam's botanical garden conserves the spiral aloe, Lesotho's improbable national plant.

What you actually see

• Inside the wall - the gallery tour through the arch's concrete heart.
• The reservoir arms - the drowned valleys mirroring the Maluti ridges.
• The Katse road - the high-pass drive in, a destination itself.
• The spiral aloes - the national plant in the dam's botanical garden.

When to go

October to April for open passes and green mountains; winter snow can close the high road and dusts the ridges photogenically when it does not. Tours run on set times - confirm before building the day around one.

Honest expectations

It is a long mountain drive for an engineering visit - wonderful if dams and roads stir you, a lot of hairpins if not. Village accommodation near the wall is simple. Water levels vary with the years; a low reservoir tells a drier story than the postcard. Photography inside the wall is restricted on some tours.

Nearby

The Bokong Nature Reserve up the road, Thaba-Tseka and the central ranges.