Todd Bolen/

HERODIAN CISTERN. Water was collected in both covered and uncovered cisterns. Dating to the first century B.C.E., this covered cistern comes from the elaborate palace fortress of King Herod the Great at Herodium in the Judean Wilderness. The ancients knew that water was essential for survival, but they also knew that contaminated water could cause sickness and even death. Although covered cisterns limited what pollutants might drop into the water, they ran the risk of growing algae.