The city is an amphitheatre facing its own bay.
Algiers does not sit beside the sea: it tips over it. The city occupies a hillside dropping in tiers to the bay, so that almost any street ends up showing you the water. That amphitheatre form explains the Casbah, the white colour, and why here you always walk uphill or downhill.
01 The shape decides
The result is that almost no street is level. You go up or you go down, and along the way the water appears in the gap between two buildings. The city spreads across the coastal hills known as the Algiers Sahel and spills inland towards the Mitidja plain.
And there is a nickname that sums up the effect: Alger la Blanche, "Algiers the White", for its whitewashed buildings. Seen from the sea, or from any height, the city throws the light back in one piece.
02 Four hundred and seven metres of fall
The figures give the amphitheatre its measure. Downtown sits at 2 metres above sea level; the average across the whole metropolitan area is 45 metres; and the highest point reaches 407, at the summit of Bouzaréah. Which is to say: between the quayside and the top of the city there are more than four hundred metres of climb.
The metropolitan area covers 1,190 square kilometres and the urban zone 443. In 2025 around 4,325,000 people lived in the urban area. It is by a wide margin the country's largest concentration.
03 The upper city and the lower one
The historic Casbah has been on the UNESCO World Heritage list since December 1992, under cultural criteria ii and v. And its internal organisation repeats the logic of the slope: there was an upper city, al-Gabal — "the mountain" — made up of some fifty small quarters, and a lower city, al-Wata, "the plains".
Five gates gave access to the enclosure, and from each gate a road ran in, dividing it. That scheme — five entrances, five axes, fifty quarters — is what you try to recognise once inside, and what you lose within ten minutes of walking.
The house type is the logical answer to a street that is steep and has no width: an almost blind façade outwards and an arcaded courtyard inwards. What other cities solve with a square, this one solves behind a door.
04 Where the name comes from
The city's Arabic name, al-Jazāʾir, means "the islands", and refers to four main islands that lay off the western cape. It is a name that no longer describes what you see: the city grew, the port was built, and those islands stopped reading as islands.
It is worth keeping in mind when you look down at the port. That front of breakwaters and quays that today looks like one continuous piece of engineering is built over the thing that named the whole city.
05 How to walk it
Start at the top and go down. It is the only sensible way to walk a city with four hundred metres of fall, and it is also how it reads: from above you understand the shape; from below you only see the street in front of you.
Inside the Casbah, forget the map. The fabric answers to the gradient, not to a grid, and the useful references are not street names but direction: go down and you reach the sea; go up and you reach the top. That is enough.
And bear in mind that Algeria requires a visa for most nationalities, with a process worth starting early. This is not a destination you improvise your way into, and that too is part of why it appears so rarely in everyone else's photographs.
