The Portrait of Water Tank This photo exhibition presents the diversity of water tanks and invites viewers to find fun in noticing the common items that surround them. Some 20 A2 sized photos have been placed throughout Metropolitan Waterworks Authority Maen Si, a place of historical significance to Thai plumbing. While water tanks may be so common as to be overlooked by people in their daily lives, apart from serving as landmarks when giving directions ie. "My house is by the large water tank", each tank is actually unique and interesting both in terms of form and function.