Archaeology is the study of past human life and culture through systematically examining and interpreting the material remains left behind. These material remains include archaeological sites (e. g., settlements, building features, graves), as well as cultural materials or artifacts such as tools and pottery. Through the interpretation and classification of archaeological materials, archaeologists work to understand past human behavior. In some countries, archaeology is often historical or art historical, with a strong emphasis on culture history, archaeological sites, and artifacts such as art objects. In the New World, archaeology can be either a part of history and classical studies or anthropology. The exact origins of archaeology as a discipline are uncertain. Excavations of ancient monuments and the collection of antiquities have been taking place for thousands of years. It was only in the 19th century, however, that the systematic study of the past through its physical remains began to be carried out in a manner recognizable to modern students of archaeology. What is the central idea of this passage?