Water engineering, sewerage and gas manufacture This collection was created in 1908. It contains archival documents, drawings of the Lesser Town water plant from the late 18th century, the plan of Hradcany aqueduct from 1835, a picture of the first Prague gas plant built in 1847, photographs from construction of water plants and other documents. The collection of three-dimensional exhibits consists of models of water engineering constructions, parts of water and sewerage pipings and fittings, water measuring devices and models of health technique devices.