It has been called the city of miracles - where the blind are made to see, the deaf to hear, and the lame to walk. Could the waters of Lourdes in fact contain mysterious healing properties? The story began in 1858, in the remote mountain village of Lourdes, France, when a 14-year-old Bernadette Soubirous is said to have witnessed a vision of the Virgin Mary. Since then, believers from all over the world have traveled there in hopes of experiencing the alleged healing powers of the sacred waters. For almost 150 years, scholars, doctors, and even key figures within the Catholic church have struggled to separate fact from faith. In this penetrating documentary, interviews with skeptics, as well as those who claim to have been healed by the water's powers, serve to paint a balanced portrait of this most enigmatic phenomenon.

• Leonard Nimoy