Many of the objects left behind by past human societies are not present in the archaeological record because they have disintegrated over time.
The material remains that still exist after hundreds, thousands, or millions of years have survived because of favorable preservation conditions in the soil or atmosphere.
The archeological record encompasses every area of the world that has ever been occupied by humans, as well as all of the material remains contained in those areas.
Archaeologists study the archaeological record through field surveys and excavations and through the laboratory study of collected materials.
Archaeology became established as a formal discipline in the 19th and early 20th centuries.
At that time, most archaeological work was confined to Europe, to the so-called cradle of civilization in southwestern Asia, and to a few areas of the Americas.
Archeology is the scientific study of past human culture and behavior, from the origins of humans to the present.