[Original 1931 text] "The Great Bath, which I have reserved to the last, was part of what appears to have been a vast hydropathic establishment and the most imposing of all the remains unearthed at Mohenjo-daro." (Marshall, Vol. I, p. 24)
The "great bath" is without doubt the earliest public water tank in the ancient world. The tank itself measures approximately 12 meters north-south and 7 meters wide, with a maximum depth of 2.4 meters.
The Great Bath is situated along a north-south street with a drain covered with limestone blocks. In the background is the so-called Granary, while in the foreground are the walls of several domestic structures.
At the foot of the stairs is a small ledge with a brick edging that extends the entire width of the pool. People coming down the stairs could move along this ledge without actually stepping into the pool itself.
The side walls of the tank were constructed with finely fitted bricks and a thick layer of bitumen (natural tar) was laid along the sides of the tank to keep water from seeping through the walls and up into the superstructure.