The frontiers of the Roman empire together form the largest surviving monument of one of the world's greatest states. They stretch for some 7,500 km through 20 countries which encircle the Mediterranean Sea. The remains of these frontiers have been studied by visitors and later by archaeologists for several centuries. Many of the inscriptions and sculpture, weapons, pottery and artefacts created and used by the soldiers and civilians who lived on the frontier can be seen in museums. Equally evocative of the lost might of Rome are the physical remains of the frontiers themselves. The aim of this series of booklets is not only to inform the interested visitor about the history of the frontiers but to act as a guidebook as well. The frontier in Lower Germany was one of the earliest to be created; surviving into the early 5th century, it illustrates the whole range of Roman military installations. In the Rhine delta, the watery nature of the landscape has ensured incredible survivals in the form of organic remains including ships. Upstream are great military bases created for the army poised to invade Germany, supported by forts and fortlets, all modified over time.