Mansell Collection, London

The earliest explorers. In the late 19th century, the London-based Palestine Exploration Fund (PEF) hired skilled engineers and military surveyors like Lieutenant Charles Warren to survey and map the Holy Land. Warren—a Royal Engineer who later won renown as the police commissioner who hunted Jack the Ripper—led the PEF’s exploration of the City of David, exploring the waterworks beneath the city. While mapping a water tunnel constructed by King Hezekiah in the eighth century B.C.E., Warren discovered the underground tunnel and shaft system that now bears his name.