ttabet, it is strange that you have never heard of Zamzam Water.

However please find the link of wikipedia who would like to know about Zamzam water.

http://en.wikipedia.org/wiki/Zamzam_Well

You will also get informaton from the below link of Arab News.

http://www.arabnews.com/?page=21&section=0&article=75881&d=11&m=1&y=2006