in Athens, Greece. Much of the original marble which formed the roof and frieze now forms a pile of rubble at its base.]] This article is about ruins in architecture; for other meanings, see Ruins . Ruins is a term used to describe the remains of man-made architecture: structures that were once complete but which have fallen into a state of partial or complete disrepair, due to lack of maintenance or deliberate acts of destruction. Natural disaster, war and depopulation are the commonest root causes, with many structures becoming progressively derelict over time due to long-term weathering. There are famous ruins all over the world, from ancient sites in China, the Indus valley and Judea to Zimbabwe in Africa, ancient Greek, Egyptian and Roman sites in the Mediterranean basin, and Incan and Mayan sites in South America. Ruins are of great importance to historians, archaeologists and anthropologists, whethe