Sometimes referred to as a "ritual bath" or "ritualarium", the mikveh has been a cornerstone of Jewish life throughout history, and remains so even today.
A mikveh is a small body of naturally collected water connected to the ground. It may be a natural pool, as in a lake, or specifically constructed, as we find in many communities. The ancient mikvehs found througout Israel perfectly conform to the way they are built today.
Many people are unaware that mikveh was an integral part of daily life for men and women in the time of the Temple. Immersion in a mikveh was part of the preparation necessary before entering the Temple, an area of elevated holiness.
Mikveh was also a requirement for eating from the offerings. In fact, just as today the hands are washed before eating bread, in the times of the Temple the hands would be dipped in the waters of a mikveh before eating from an offering. One can understand why so many mikvehs are found in the excavations around the Temple Mount.
It should be noted that mikveh has nothing to do with physical cleanliness. It is, rather, a vehicle for spiritual elevation.
Every mitzvah (commandment) can be understood on a myriad of levels, and mikveh is no exception. A full discussion of mikveh is beyond the scope of our tour, but we can gain an inkling of its potential by examining the meaning of the number in its measure.
The Oral Tradition tells us that the size of a mikveh is 40 seah of water. (Seah is an ancient unit of volume. 40 seah is approx. 198 gallons or 750 liters.)