How did they build the retaining stone walls along river banks in cities hundreds of years ago?



Struggling to explain what I mean, every major city/river/harbour doesn’t have a natural coast line, but generally a stone wall that goes down into the river and creates a permanent solid edge. I’m sure with modern technology its easier, but the ones built hundreds of years ago baffle me. Tried googling it but got a combination of Minecraft, retaining wall and river rock information..

In: Technology

5yo version: There’s a few ways. One way is that they build a wall in the water where they want to work and then use buckets to take out all the water. So they can work on dry ground. Another way is just dump stone and earth into the water where they want the wall and then when it’s shallow enough they build a nicer wall above water. As others have mentioned, they could also divert rivers, but you can’t really divert the ocean! The chief exception being the sea dykes in Denmark!

Here’s an awesome animation of how it was done: [](

I guess it depends on how far you want to go back and what you mean by “how was it done”. Generally in pre-industrial times you would obtain rock from a local quarry and have it brought to an area you wanted to build up. This was usually done by things like pulling it on a cart using a beast or large groups of workers.

Once the stone was on site they would just use the applicable masonry techniques for the time and area they were in.

A Cofferdam is what you are looking for. Used in lots of situations like you mention.