As you approach over the flat farmland, something vast and cone-topped appears over the horizon which you would be forgiven for thinking is a hill. It is, instead, a mausoleum and one of Algeria’s many archaeological mysteries. The mausoleum is 18.5m high and 59m in diameter, and composed of a vast number of cut stones laid over a rubble core. It is an imposing construction, a circular base with a conical roof. It was built out of massive stone blocks, the base decorated with 60 columns topped with Doric capitals. It was obviously intended as a royal burial place: there is a false door and a real, hidden entrance that leads – via steps to a corridor and then a cedarwood door – to the empty burial chamber beyond. Now for the mystery: it was long assumed this was the burial place of Micipsa, son of the great Numidian king of Massyli, who died around 119 BC. But carbon dating suggests that it was built earlier, perhaps before the 4th century BC, though for whom it is not known. Whenever it was constructed, the mausoleum is evidence of a sophisticated people, influenced by Berbers and Libyans, Carthaginians and Greeks, and who knew how to cut and manipulate massive stones with great accuracy. The mausoleum lies some 34km northeast of Batna: heading towards El-Khroub and Constantine, the turn-off onto the W165 is on the right. Public transport (either bus or taxi collectif running along the Batna– Constantine road) can drop you near the turn-off, but it is a long walk and there is little local traffic. Unless you have your own transport you will need a private taxi (around DA1000 including a little waiting time).