Inselberg

Click: forest elephant, stern and alert. Click: humpback whale, breaching skyward like a frisky trout. Click: Gaboon viper, its big coppery head so close to the lens you could almost feel the flick of its tongue. Click: granite inselberg, like a great igneous gumdrop, protruding above forest canopy. Click: bulge-eyed hippopotamus, almost unrecognizably strange and serene, riding a wave along the Atlantic coast.

From the north, the road into Nigeria’s purpose-built capital is strewn with inselbergs, vast monolithic stone outcrops that rise abruptly out of the lush savannah. At the centre of the country, the city became the seat of government in 1991 after Lagos had become too crowded and chaotic.

Ground penetrating radar can map the foundation of Gulem menhir and establish its identity either as a natural geological oddity, a natural inselberg or a manmade menhir.