Whilst it hasn’t happened since 1978, the Vltava used to freeze over fairly frequently, although it wasn’t very safe to skate or walk across.

The change occurred when a series of dams and weirs were built downstream which mitigated the risk.

Professor Erazim Kohak was born in Prague and told Radio Prague about the times he remembered the river freezing.

“I remember the winters of my childhood as remarkably free of automobiles. We, boys, would gather in Kostelni ulice at Letna, where I lived, if an automobile would park. We would all gather around it as a curiosity. But there were not enough of them to interfere with our sledding. And I remember Prague as covered with snow, and the Vltava as frozen, with the snow swept away so that people could skate on the Vltava”

“It was not everywhere. It was specifically by what was then Smetanovo namesti. It used to be called Na Rejdisti, before it became the Square of Empress Zita, in 1917. There was one place there where a man always swept the snow away and one could go skating there,” he added.