Voltzberg is printed on the back of Suriname's twenty-dollar note: a bald dome of granite, 240 metres high, pushing up through forest that runs unbroken to every horizon. It is an inselberg — a plug of hard Precambrian rock from the Guiana Shield, left standing after the softer ground around it wore away over hundreds of millions of years. A young German geologist, Friedrich Voltz, saw it from the river in the 1850s and was dead of yellow fever in Paramaribo at twenty-seven; the mountain kept his name. Suriname gave it protection: in 1998 the dome was folded into the Central Suriname Nature Reserve, 1.6 million hectares of forest covering roughly a tenth of the country, listed by UNESCO in 2000. Nobody lives inside it, nobody hunts inside it, and no road reaches it. You arrive by boat up the Coppename River, past the rapids of Raleigh Falls, and then you walk.
The trail runs six kilometres and three to four hours through primary forest, over creeks bridged with fallen trunks, under trees whose roots stand higher than you do. Somewhere off it, orange cocks-of-the-rock hold their lek. Then the trees stop and the rock begins: coarse charcoal-grey granite, so steep in places that you climb on your hands, dotted with cacti and lizards — a scrap of drought country perched above the rainforest. From the top the canopy spreads out like a green sea, other bare domes standing up out of it like islands, and macaws cross below you as they leave their roosts. It stays a serious trip. There is no lodge and no shelter on the mountain; you come with a licensed operator, sleep on an island in the river, and camp at the foot of the rock.