Urban archaeology is a sub discipline of archaeology specializing in the material past of towns and cities where long-term human habitation has often left a rich record of the past. In modern times, when someone talks about living in a city, they are in an area with many surrounding people and buildings, generally quite tall ones. In archaeological terms, cities give great information because of the infrastructure they have and amounts of people that were around one another. Through the years there has been one big method used for Urban archaeology along with significant historic developments. Large concentrations of humans produce large concentrations of waste. Kitchen waste, broken objects, and similar material all need to be disposed of, while small numbers of people can dispose of their waste locally without encouraging vermin or endangering their health. Once people began to live together in large numbers, around five thousand years ago, such methods began to become impractical and material usually was brought into these new settlements but would rarely be taken out again. Urban archaeology can be applied to the study of social, racial, and economic dynamics and history within contemporary and antiquated cities as well as the environmental impacts within these spaces.Up until the nineteenth century when organized rubbish disposal became widespread in urban areas people invariably threw their waste from their windows or buried it in their gardens. If their houses fell down, a common enough occurrence when planning laws were non-existent, owners would pick out what they could reuse, stamp down the remains and rebuild on the old site. Archaeological excavations of urban sites are often categorized by these remains and as well as the former impacts of modern technology such as sanitation, commercial, or transportation services The effect of this is that even a moderately sized settlement of any antiquity is built on top of a heap of refuse and demolished buildings and is therefore raised up from its original height on a plateau of archaeology. This is most apparent in the tel sites of the Near East where towns that have been occupied for thousands of years are raised up many metres above the surrounding landscape. In walled towns, such as those in medieval Europe, the effect of the encircling defenses was to hold in the waste so that it could not slip outwards, magnifying the effect. Redevelopment and archaeological excavation is a part of modern urban life and public interest in urban archaeological work is often strong, yet developers can be cautious of unbridled dissemination of information that has the potential to ignite public opinion. Urban archaeology carries the opportunity for archaeologists to work with the public to illustrate the history and heritage of discoveries. Source: Wikipedia (en)