While wandering around the nature reserve in Essex the other day I came across these remnants of an old pier. A little further inland there is a massive concrete wall, with signs of a futile attempt at explosive demolition.
An explanatory notice by the wall indicated that these are remains of a former sand and gravel extraction plant, of which there are a number in this area along the River Colne. What is now a wildlife reserve was once an industrial site.
Driving away later, I went along a single carriageway road with passing places - seemingly newly-surfaced. It went through a very odd piece of landscape with earth piled on either side. When I parked and looked over one of these ramparts, I found present day extraction going on, with a mechanical digger shovelling sand into a hopper feeding a conveyor belt that headed away into the distance.