YUnder the kitchen sink.
Our 50 plus year old house has most of the pipes in or under the concrete slab floor. It is very scary to look at some of the hidden plumbing connections. Like that pictured above under the kitchen sink. The above pipe image was shot in digital color with seven images of various exposures. I used 5 of the 7 to make the composite image and then convert it into a monochromatic photograph.