Coming from The North Wales coast road and crossing the Dee via the new bridge, a little further on after the paper mill, you, pass - on your left - Shotwick Lake sailing club. Across the fields near the eastern extreme you can see a strange shed or building. It is painted light green and obviously houses something tall inside.

A bit over a km further along the A548, you can see another identical one.

I have wondered about them for years, but getting to them seems pretty difficult. What roads there are are either blocked by locked gates or suitable only for those driving a tank.

Anyone got any idea what they are?

something to do with firing ranges? Storage for whatever crops are grown there--think ive seen them harvesting spuds.

They are both also right on the border between wales (19) and england-(28) sorry just had to get that in

Believe it or not, they're electricity sub-stations! We went up the farm track when we were looking for a path that would take us into Puddington village while out walking. They had "danger of death" signs on them with the company name Corus, so presumably owned by the steelworks

Well, thanks for that, Cobby. Presumably there are pylons feeding them? I haven't noticed them from the dual carriage way, but I wasn't looking for them and probably at that distance they are not obvious.

The area seems peppered with odd constructions. There is an installation near the reservoir next to the main road with a sort of domed concrete construction for instance. I assume its something to do with the reservoir and the two lagoons next to it, although I wonder why there is a reservoir there anyway...

Water for the power stations?

Power stations use water to dump waste heat into, but I suspect they'd use the the river to do that. More likely to be to do with the paper mill I suspect.