It is amazing what can be found hidden under London. Built in the middle of the 19th century this abandoned/disused covered victorian reservoir is a testament to the quality of workmanship there was back then.
Large arches continue at length in seperate blocks. It must be at least ten blocks wide maybe more, I would guess it is at least 50m square. It is a little bit hard to judge when you can not see from one end to the other.
Shot in complete darkness mainly using two strobes/flashguns for lighting. Which was novel as I have not tried it before. It really was a great adventure, even though I got a little bit wet on arrival.
Later on in 2014 I had the pleasure of visiting Swithland Underground Reservoir. Not quite as grand but still an interesting location.