In archaeology, Earthworks are artificial changes in land level often known as lumps and bumps. Archaeology, archeology, or archæology (from Greek grc ἀρχαιολογία archaiologia – grc ἀρχαῖος archaīos They can themselves be features or they can show features beneath the surface. Feature in archaeology and especially Excavation has several different but allied meanings  Earthworks of interest to archaeologists include ancient fortifications, henges, mounds, tumuli and other tombs. henge is a prehistoric Architectural structure. In form it is a nearly circular or oval-shaped flat area over 20 Metres (65 feet) in diameter A mound is a general term for an artificial heaped Pile of Earth, Gravel, Sand, rocks A tumulus (plural tumuli) is a Mound of earth and stones raised over a grave or graves For the New York prison see The Tombs. A Tomb is a repository for the remains of the dead. Earthworks from deserted medieval villages can be used to determine the location, size and layout of lost settlements. Deserted medieval village (DMV sites are former settlements which have been abandoned for one reason or another over the years usually leaving little but the remains of earthworks
Earthworks can vary in height from a few centimetres to the size of Silbury Hill - 40 metres. Silbury Hill is a 40-metre (130-ft high man-made chalk Mound near Avebury in the English county of Wiltshire. They can date from the neolithic through to last week. The Neolithic (from Greek νεολιθικός — neolithikos from νέος neos, "new" + λίθος lithos They can stretch for many tens of kilometres, e. g. Offa's Dyke. Offa's Dyke (Clawdd Offa is a massive linear earthwork, roughly following some of the current border between England and Wales.
Shallow earthworks are often more visible in aerial photographs taken when the sun is low in the sky and as a result, shadows are more pronounced. Aerial photography is the taking of Photographs of the ground from an elevated position Similarly, earthworks may be more visible after a frost or a light dusting of snow An accurate survey of the earthworks can enable them to be interpreted without the need for excavation.