Apparently it moves, constantly shifting before the Indian Ocean winds that sculpt Mozambique's shores, but, as I peer downwards, it feels pretty solid beneath my feet — or, should I say, my board. One shove and I'll be flying down this hot powdery slope balanced precariously on a snowboard and shrieking with pleasure.
Dune-boarding is just one of several firsts I try at Indigo Bay resort on Bazaruto Island, the largest of the eponymous archipelago that lies a quarter of the way up the Mozambican coast. At dawn I'd been cantering along the beach, even though I can't ride — which wasn't frightening, thanks to Gustav, the Afrikaans horse whisperer in charge of the stables, who possesses equine powers of communication and makes my mount stop simply by saying 'ssshhh'.
Later we dived the Potholes, a series of giant fish-filled coral bowls like no site I'd ever dived before. The Bazaruto Archipelago certainly is Mozambique's playground. It's also the country's most important national park and has been welcoming tourists for decades - even during the civil war, thanks to direct flights from South Africa and game fishermen who wouldn't be put off.
Nowadays, an ever-increasing host of lodges and small hotels jostles for position at Vilanculos, the mainland hopping-off point for the islands. Bazaruto and Benguerra, the two largest (large being relative: Bazaruto is 35x7km), host a handful of upmarket properties, including Indigo Bay, a small luxurious hotel with open-air bars and lounges, air-conditioned bungalows and tranquillising views of dune and sea. Although Bazaruto is just 600km up Mozambique's 2500km coast, it represents an invisible north-south divide, as far as tourism goes.
Above the Bazaruto barrier lies a largely undeveloped Swahili-flavoured shore, serviced by a sparse infrastructure and studded with historical treasures from Portugal's colonial days. The region is a palimpsest of African origin, with Arabic, imperial Portuguese and outlines of modern western script layered upon one another.
With its healthy infrastructure and a coastal tourist industry that has burgeoned since 1992's ceasefire, the south is almost another country, sheltering beneath the umbrella of the capital, Maputo, in itself suckled by the regional giant Johannesburg. South African accents ring through the five-star hotel bars of the sensitively refurbished Polana or the slick new Avenida.
One curio seller I haggle with pulls out his mobile phone. In common, north and south share a sensuous laid-back ambience born of Africa having met the Mediterranean. At Costa do Sol, a shore-side Maputo institution that has been serving spicy piri-piri prawns to the city's well-heeled since 1938, the flavours of garlic and Portuguese wine mingle with the sounds of African hip-hop from the car stereos of boys selling drinks by the beach.
A short walk from the Mercado Central, throbbing with vegetable colour and piscine smells, is the icy elegance of the mint-green and cream railway station, a colonial confection built to link then-Lourenço Marques to the gold-rich Rand. Near the gothic frills of the Natural History Museum, displaying an extraordinary moth-eaten collection of taxidermal drama and elephant foetuses, is the Nucleo de Arte, with its casual exhibition of sculptures made from civil war weapons.
Here's a memorial to Afrikanerdom's Great Trek leader, Louis Trichardt, who allegedly died in the city from malaria; there's the mansion shared by Africa's first couple, Nelson Mandela and Graça Machel. I contemplate Maputo's wonderful contradictions in the most European of ways, over espresso at a pavement café, while those most African of characters, the curio sellers, parade ingenious wares before me.
This city is easy on its visitors, letting them choose its identity: South African burgers and M-Net TV in a sports bar, or fabulous crab curry under neon lights with multi-hued Maputans at the Feira Popular. The further north you venture, the more you must take Mozambique as you find it. Above Vilanculos's metaphorical dividing line lies the ultimate physical barrier: the mature Zambezi, fat and voluminous, well fed by tributaries and sliding towards its gaping estuary.
Historically, it kept north and south separate; even today, only a car ferry links the two at Caia, where the coast road crosses the river. Above the Zambezi, roads crumble and distances are huge. Tourists with time considerations are best advised to fly to Nampula or Pemba to access this extraordinary region.
From Nampula, a couple of hours' drive on bumpy tar brings you to one of Africa's — of the world's — most surreal places, Ilha do Moçambique. UNESCO acknowledged its uniqueness in 1992, awarding the former Portuguese capital World Heritage status.
I'm careful not to trip over loose 16th-century cannon balls while strolling the weedy ramparts of São Sebastão Fortress in disbelieving solitude. Just 2.5km long, this film set of an island has a palace stashed with intricate Goan and European furniture, a disproportionate number of churches, streets of ruined villas and a vast decrepit hospital.
Its thriving reed-hut village supports 7000 people, who frequent the pretty mosque and sell fish and coconuts with careless grins. This end of Mozambique definitely doesn't let you choose, but accept it for what it is and it's intoxicating. At Pemba, Portugal takes a back seat to unsullied Africa.
Makua women sport skin-softening facemasks of white paste. Makonde carvers work chunks of liquorice-like ebony — pale on the outside, dark within — into powerful human forms. A brightly-coloured crowd of women and children sits peacefully below majestic mango trees, marking the day when the community's sons go to the bush for initiation into manhood.
The mothers have shaved their heads for the occasion. We watch children playing between beached dhows at sunset, boys showing off with backflips, girls parading with garlands of curly seaweed round their heads and hips, Polynesian-style. Leaving the Swahili-tinted comfort of the new Pemba Beach Hotel, we board a tiny old plane heading north over a shore where sea meets bush and nothing is man-made.
The north's staggering emptiness hits home. We overfly a string of islands and land in a coconut plantation, before transferring by boat to the tiny private-island resort of Quilalea. In airy chalets with interiors of rich wood and billowing white muslin, we live in barefoot luxury that could hold its own in any ocean.
A gleaming speedboat takes us game fishing en route to Ibo Island, where we abandon sybaritic indulgence for historical fantasy among the shells of 18th-century houses that people in Europe would pay millions for just to restore. In the old slave fortress silversmiths produce impossibly intricate jewellery from old molten coins.
We rush back to Quilalea before the tide cuts us off, to dive in the surrounding marine sanctuary. At sunset we sip iced beers beneath the squeaking rig of a dhow in a sea of molten bronze. Maputo seems a world away; even Bazaruto, with its air links to Johannesburg.
Britain may fret about its north-south divide, but Mozambique should take pride in its dual identity: it makes travel in this beguiling country doubly rewarding. Time will erode the logistical contrasts, but in personality Mozambique will always be split.
Mozambique in a Nutshell
In the far south are endless dune-backed sands at Ponta do Ouro and Ponta
Malongane, beloved by South African fishermen and divers. Outstanding palm-fringed beaches occur throughout Inhambane Province, especially within 30km of Inhambane town.
To the north are Tofo and Barra beaches; to the secluded south, Jangamo and Paindane Beaches and Coconut Bay. Consisting of sand dunes, the Bazaruto Islands are all fringed by kilometres of unbroken, untouched beach. Wimbe, outside Pemba, is a long strip of white sand with bars and a dive centre. The Quirimbas, 27 offshore islands of fossil coral rock in the far north, harbour innumerable intimate castaway beaches.