Sites containing signs of the first simple but purposeful burials in graves date to as early as 40,000 years ago in Europe and Southwest Asia.
By the time people lived in civilizations, burials and funeral ceremonies had become extremely important and elaborate rituals.
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.
Laetoli even reveals footprints of humans from 3.6 million years ago.
Some sites also contain evidence of the earliest use of simple tools.
For instance, archaeology tells the story of when people learned to bury their dead and developed beliefs in an afterlife.
Archaeology plays a major role in the study of early civilizations, such as those of the Sumerians of Mesopotamia, who built the city of Ur, and the ancient Egyptians, who are famous for the pyramids near the city of Giza and the royal sepulchers (tombs) of the Valley of the Kings at Thebes.
Other sites that represent great human achievement are as varied as the cliff dwellings of the ancient Anasazi (a group of early Native Americans) at Mesa Verde, Colorado (see Mesa Verde National Park); the Inca city of Machu Picchu high in the Andes Mountains of Peru; and the mysterious, massive stone portrait heads of remote Easter Island in the Pacific.
Archaeology is an important field of anthropology, which is the broad study of human culture and biology.
Archaeologists concentrate their studies on past societies and changes in those societies over extremely long periods of time.