Villages and towns are often found at bridging points, but it is usually not a good idea to build too close to the river.
Yarm has had serious flooding problems and makes regular use of its floodgates.
The Thames barrier is used to protect London, and numerous other flood protection measures are in place on other rivers, to protect other adjacent built-up areas.
Of course, some settlements are built away from the bridge, like here at Carrog.
But finding a dry spot is not always easy. In some areas the land is flat and low and, if left in its natural state, would be decidedly boggy.
If it is like that for miles and miles, where do you build your town?
You need a spot that rises up, just a little, above the general flat land. It will then be a little bit drier, so easier to build on, and also a good vantage point from which to keep an eye on the surrounding land.
Here at Ely, the surrounding land has now been drained, but when the town was founded it was built on an island of dryness rising above the boggy, flat fens. The area is still labelled as Isle of Ely on maps…
…and as you walk into town there is a definite hill to climb.