At the end of 3rd and at the beginning of the 4th century, a new Roman waterworks – the Aqueduct - was built to supply the Diocletian Palace with water from the river Jadro. This 9 km long gravitational waterworks is considered to be one of the first waterworks in the Croatian area.
Still today the aqueduct and tunnels of the Roman waterworks are used to supply the town with water. Part of the Diocletian aqueduct can be seen in the exhibition area of the underground rooms of the Atrium hotel as well as by entering the waterworks channel.