All have perished in the numerous sieges and inundations which have devastated the city.
There is evidence that, towards the close of the mediaeval period, great storms and tidal inundations occurred on the shores of the North Sea and Baltic, and in the course of these floods, culminating in 1297, the Zuider Zee was formed from a lake that existed in its neighbourhood, by the breaking down of dykes.
The city, said to be the "Eden" of Charles Dickens's Martin Chuzzlewit, is built on a tongue of land between the rivers, and has suffered many times from inundations, notably in 1858.
The valley in which the town is situated used to be subject to inundations, but in 1805 a tunnel was constructed by means of which the surplus waters of the Bied are carried into the Doubs.
The ordinary rise and fall of the river is comparatively slight, but when the west wind blows steadily for a long time, or when Lake Ladoga sends down its vast accumulations of block-ice, inundations of a dangerous kind occur, as in 1777, 1824, 1879 and 1903.
