The engineers also built reservoirs, diversion dams, levees, aqueducts, and canals. Roman building ingenuity extended over bridges, aqueducts, and covered amphitheatres. These included supervising the building of aqueducts and canals. The Minoans used technologies such as wells, cisterns, and aqueducts to manage their water supplies. During this time, dams, aqueducts and railroads were built. Throughout the Roman empire, their engineers erected arch structures such as bridges, aqueducts, and gates. They are commonly found at the ends of long embankments and at aqueducts. Locks were widened and/or rebuilt in new locations, and many new navigable aqueducts were constructed. The simplest aqueducts are small ditches cut into the earth. The Romans improved crop growing by irrigating plants using aqueducts to transport water. Three other suspension aqueducts were subsequently built for the canal. Hundreds of similar aqueducts were built throughout the Roman Empire. Telford designed a number of bridges and aqueducts during his career. The vast system of Roman aqueducts also made extensive use of hydraulic cement. Some of the Roman aqueducts still supply water to Rome today.