Megiddo has been excavated three times in the past, and has yielded some of the richest finds ever found in Israel. Gottlieb Schumacher conducted the first excavations at the site from 1903-1905, on behalf of the German Society for Oriental Research.
In 1925, excavations at Megiddo were renewed by the Oriental Institute of the University of Chicago. This large-scale undertaking, directed successively by Clarence Fisher, P.L.O. Guy and Gordon Loud, continued until the outbreak of World War II in 1939. These excavations revealed twenty major levels of occupation, covering the entire history of the site. The most important remains were the sacred compound, the monumental fortifications and gates, the impressive water systems of the site, various palaces, and the so-called 'Solomonic stables'.
Yigael Yadin carried out a few short seasons of excavation at Megiddo in the 1960s and early 1970s on behalf of the Hebrew University of Jerusalem. He partially uncovered the monumental Palace 6000, generally attributed to King Solomon, in an attempt to clarify the complicated stratigraphic problems related to the Iron Age remains at the site.
The previous excavations at Megiddo laid the foundation for the discipline of biblical archaeology. However, archaeological methods were still in their infancy and nearly every layer and major architectural feature, in fact, almost every wall and vessel unearthed at the site, has become the focus of fierce scholarly dispute (see, for instance, The Chronology Debate in the Publication section).