A crinkle crankle wall

I have always wondered about this wall and the other day I discovered, quite by accident, that it had a name. Apparently, according to Google, it is an economical way to build a wall since it only needs to be one brick thick. If it were straightened out it would easily topple over and if it were double thickness it would use many more bricks.
The bit you can see is only a couple of feet tall but on the other side there is a 20 foot drop. I don't know how old it is but I reckon the top bit has been renewed recently. The lower, retaining part seems to be much older so it appears to have stood the test of time.