Anchored tenuously in the deep Indian Ocean, this giant island is still as wild and unpredictable as the Victorian-era jungle-seekers dreamed. Millennia of chaos erupting from the earth’s toxic core or from the fierce ocean waves create and destroy in equal measure. When the earth and sea remain still, the past’s death and destruction fertilise a verdant future. The rugged mountains and fertile valleys are fed by near-constant rains, colouring the jungles of the Mentawai Islands and the rice terraces of Bukittinggi many shades of green.

Don’t come looking for a holiday, that’s Bali, or empire builders, that’s Java. Sumatra is an adventure, the kind of demanding ride that requires a dusty knapsack and tough travelling skin. Climb up the smoking volcano craters that ring the hill town of Berastagi, slog through muddy jungle paths and spot a wild orang-utan high up in the canopy at Bukit Lawang, or scuba dive through a sculpted underwater landscape at Pulau Weh. Endure the Sumatran spin cycle and earn your rest amid a picturesque volcanic lake at Danau Maninjau, where you can slip into the morning mist and swim through the land before time.

Sumatra is still visibly diverse, with more than 52 tribal languages and the full spectrum of societal organisation. In a few remaining pockets, hunter-gatherer tribes collaborate with the jungle for survival. Other tribes have sewn together the expectations of the outside world with their own customs. The Bataks of Danau Toba; the matrilineal Minangkabau of West Sumatra – each bus ride will deliver you to another tribal heartland.