A fine example of the sophisticated engineering of the ancients… As suggested by the name, this tunnel was built under the reigns of the Roman emperors Titus and Vespasian. Despite the evident lack of creativity in giving it a name, the tunnel is a really impressive example of Roman engineering, designed to divert the waters that constantly threatened to flood the town of Seleucia. This is a task it performed admirably for centuries, and you can still see how today.