I was easily pleased

I was called out today to do a repair on a welfare cabin which happened to be at a reservoir. It was the type of reservoir that is half in the ground and half above, basically a big tank. I was lucky enough to be given a quick tour, WOW what an amazing place, about 300ft x 150ft x 15ft. The place echoed beyond belief, and seemed to suck the light from the torch with out giving light to see. The other thing I noticed was there seemed to be no depth of vision, it did not seem as big as the measurements I had been given. But when you look at the mound from the out side you could see the size. I like all things different, so this is one I can now tick of my to do list.
Sean

Please tell me you took a picture, cause its hard to decipher what your saying.
Are people living in this " Tank" ? Or is it for holding water ?

I was not able to take a picture, and the tank was being inspected so that it could be refilled with water, that feeds an area of north London with drinking water.
Sean

Here is a link to a undergrond reservoir.
Sean
http://www.google.co.uk/imgres?imgurl=http://www.porg-volders.tsn.at/bilder/2004/Komprimiert5AExM%25FChlauBild2.jpg&imgrefurl=http://www.porg-volders.tsn.at/english/globalcitizenship/waterworks.htm&usg=__evPqcOVxUyDfyYzI6SiTc4hGBJ0=&h=1200&w=1600&sz=30&hl=en&start=26&zoom=1&tbnid=HWmLjlliXdmTXM:&tbnh=113&tbnw=150&ei=F94ATrrlCciy8gOqrfi8DQ&prev=/search%3Fq%3Dunderground%2Breservoir%26hl%3Den%26rlz%3D1B3GGHP_en-GBGB431GB432%26biw%3D1600%26bih%3D715%26tbm%3Disch&itbs=1&biw=1600&bih=715