The world’s natural bodies of water — its oceans, rivers, wells, and spring-fed lakes — are mikvahs in their most primal form. They contain waters of divine source and thus, tradition teaches, the power to purify. Created even before the earth took shape, these bodies of water offer a quintessential route to consecration. But they pose difficulties as well. These waters may be inaccessible or dangerous, not to mention the problems of inclement weather and lack of privacy. Jewish life therefore necessitates the construction of mikvahs (“pools”), and indeed this has been done by Jews in every age and circumstance.