Five years after the opening of “Europe’s first vertical city”, the luxury apartments of the Shard reportedly remain unsold. Why? Aside from the astronomical cost – the 10 flats in the 72-storey building are together valued at £199,250,000 – there is the location. As one luxury property agent put it: “Rich people don’t want to shell out zillions living south of the river. Nobody knows anyone who lives south of the river.”

So where did London’s intractable north/south divide come from and what other cities are geographically, culturally and socially separated by rivers?

London



The divide is as embedded in the city’s identity as the Thames. The notion of the north overseeing the south dates back to Emperor Claudius, who built Londinium on the north side of the river. Apparently, it was less marshy. For the 2,000 years since, north has lorded it over south.

Paris



The Left Bank of the Seine signifies artists and thinkers – Jean-Paul Sartre, Simone de Beauvoir and the Sorbonne – while the Right Bank stands for the establishment, all buttoned-up bankers, grand boulevards and opera houses. The split began in the middle ages when the Right Bank was the first to develop through trade. But these days it’s all about east and west ...

Dublin



The Northside and Southside of Dublin, separated by the Liffey, have long been divided by social class: the north historically poorer. But it wasn’t always this way. In the 18th century, the first exclusive Georgian houses for the wealthy Protestant Ascendancy class were built on the Northside. But by the late 19th century the upper classes migrated south, following the Earl of Kildare’s decision to build his palace in there, and the Northside Georgian addresses were repurposed as tenements housing multiple families.

Budapest



Less than 200 years ago Hungary’s capital was two cities, Buda and Pest, bifurcated by the mighty river Danube. Budapest’s split personality – a city both divided and then in 1873 united by the Danube – continues, with the left bank of the river (Buda) the more historic quarter with narrow streets, a castle atop a hill, and extraordinary architecture. The right bank (Pest) is more modern, hip, flat and industrial.

Mostar



Bosnia’s world-famous Old Bridge united the people – Catholic Croats and Bosniaks (Muslim Bosnians) – on either shore of Mostar’s Neretva river for centuries, making it the most ethnically integrated city in the former Yugoslavia. But the Balkan war destroyed the bridge and, despite it being rebuilt in 2004, Mostar continues to be a city divided, with two phone networks, electricity companies, postal service and school systems.