It was designed for fifteen thousand people.

01 March 1958

That figure is worth pausing on, because it is the key to the place. Fifteen thousand inhabitants is a large village. The layouts, the street widths, the land reserves and the networks were all sized for that. It was not a careless miscalculation: it was a reasonable forecast for a country with a dispersed and largely nomadic population.

Nor was the site that of an inherited city. It is a sandy plain beside the Atlantic, flat as far as the eye reaches, with parts lying below sea level. There is no hill, no river, no natural harbour: the geography offered no prior form to build on.

02 A hundred times the plan

What happened next was on no drawing. The 1977 census gave 134,000 inhabitants; that of 1988, 393,325; by 2023 the city was around one and a half million. That is growth of almost a hundred times the projected figure, in a little over sixty years.

The engine of that leap was drought. Dry years pushed the population of the interior towards the coast, and the newly laid-out capital was the destination. In a few years the city absorbed people who were not coming to occupy the planned quarters but to settle wherever there was room, which was on the edge.

The urban result is a city of two superimposed speeds. There are the laid-out axes — wide avenues, tree-lined where possible, with regular blocks — and there is everything else, which grew by accretion outwards. The second is far larger than the first.

03 Between the dune and the ocean

The city has two edges and both are mobile. From the east the sand advances: the dunes arrive from the interior and clearing the asphalt is a daily problem, not an anecdote. You see it on any street on the outskirts, where sand takes the verge and eats into the lane.

To the west lies the Atlantic, and there the problem is the opposite: coastal erosion and rising sea level, on flat ground with areas below sea level. Greenbelts have been attempted to fix the sand at specific points, with uneven results.

04 How it is covered

It is worth adjusting expectations before arriving: there is no old town here, because there was no city before 1958. What there is is a recent capital, spread out and low-rise, in which the interesting thing is not the buildings but the relationship between the street grid and the desert.

The two places that genuinely organise a visit are at the extremes. One is the beach where the pirogues work, on the Atlantic edge, which is the liveliest part of the city and operates mostly in mid-afternoon. The other is any point on the eastern outskirts, where you can see the sand front advancing over the grid.

And there is a calendar fact that greatly simplifies planning: it rains here an average of 8.3 days a year. Rain is practically not a factor. What is are the afternoon heat between March and October and the dust haze, which can whiten the sky for days on end.