Belgrade was built with its back to the water.

01 A city that kept watch on the water

The city stands at 117 metres and the fortress at 125.5, on the end of a geological bar that runs up from the south and breaks off sharply exactly where the Sava enters the Danube. From there you command the plain to the north and west. That combination —height, a vertical drop, two rivers in front— explains why the site has been settled since prehistory and why what got built on it was, again and again, a walled enclosure.

The name of the park that now wraps around the citadel says it plainly: Kalemegdan comes from two Turkish words, kale, fortress, and meydan, battlefield. Belgrade's best-loved green space is called, literally, the open ground in front of the fortress. It became a park barely more than a century ago; before that it was the land that had to be kept clear.

Walk the edge of that wall today and you will notice a curious asymmetry. The water is at your feet, less than a kilometre away, and there is no comfortable way to reach it: you have to go around, down ramps, across a road. The city looks at the river from above, with a magnificent view and an awkward relationship. That mismatch is the subject of everything that follows.

02 1948: down into the mud

Between the two rivers, directly opposite the fortress, lay a marshy plain that flooded regularly. Nobody lived there permanently. On 11 April 1948 continuous construction began on what is now called Novi Beograd, and the first job was not to put up buildings: it was to raise the ground. Sand was pumped from the Sava and the Danube to drain the wetland and lift the terrain beyond the reach of floodwater and groundwater.

In other words: to build a city between two rivers, the ground had to be manufactured out of the rivers themselves. The municipality was formally established in 1952 and, in the 2022 census, Novi Beograd had 209,812 inhabitants. It is by some distance the city's most populous municipality, and all of it stands on alluvial sand put there on purpose.

You feel it as you walk. Addresses are not street and number: they are block and number. The buildings do not form a continuous frontage but stand as separate pieces around a shared green void, and the avenues between them have the width of a country highway. It is a scale that disorients at first and that clicks into place the moment you remember there was nothing here —no prior street plan to adapt to, not even solid ground.

03 1967: closing off an arm of the river

The second move is even more literal. Upstream of the fortress, in the Sava, lay a long island called Ada Ciganlija. Between 1957 and 1967 two dams went up, one at each tip, closing off the river's right arm. The island stopped being an island and became a peninsula; the closed arm stopped being a river and became a lake.

The numbers describing the result belong to a hydraulic project, not to a park: 4.2 kilometres long, some 200 metres wide on average, four to six metres deep and up to fourteen at the deepest point, 0.86 square kilometres of water and seven kilometres of shore turned into gravel beach. In summer the water regularly reaches 24 degrees.

From then on the city had something it had never had: a shore to go to for pleasure. On a July day more than a hundred thousand people pass through Ada, and a weekend can reach three hundred thousand. In a city of 1.2 million, a place like that gets called the sea and nobody laughs. And one detail is worth holding on to: the water comes from the Sava and forms part of the system the city draws on, so this recreational lake is also a monitored reserve.

04 Water as a place to be

The third move was nobody's plan. Along both banks the splavovi appeared: floating structures moored to the edge, with a gangway from the quay, working as restaurants, cafés and dance halls. They are not boats: they are single-storey buildings on pontoons, with a roof, a terrace and flower pots. They have an address, a menu and opening hours, and they rise and fall with the river.

There is one more piece, and it sums up this city's relationship with its water better than any other. At the very point of the confluence, in front of the fortress, sits a 2.11-square-kilometre island that has never been built on: low, largely marshy, frequently flooded by the Danube. It has been a protected landscape since 2005 and 208 bird species have been recorded on it. A capital with 1.7 million people in its metropolitan area has a floodplain forest at its most visible point.

And on the far side of the Danube is Zemun, a separate town until 1934, with its own fabric of low houses and red roofs and a long quay that is now one of the finest waterside walks in all of Belgrade. It is twenty minutes by bus and another twenty on foot. The city therefore has two shores and no centre joining them: you have to choose which one to spend the afternoon on.

05 What Belgrade leaves you

What stays with you is not one particular postcard. It is having understood, on foot, that this city has done three very different things with the same water in less than a century: used it as a moat, turned it into sand to build on, and dammed one of its arms so people could swim. None of the three is a small gesture and all three can be seen in one afternoon.

There is also a feeling that is hard to shake: that of being in a city still settling into its own geography. The quays do not yet form a continuous route, the bank breaks off, you go from a tended promenade to waste ground in fifty metres. This is not a flaw to be forgiven: it is the current state of a job that started in 1948 and that you can watch in progress.