The Grotto of Massabielle is a natural cave located in Lourdes, France. It is famous for being the site where Bernadette Soubirous reported 18 visions of the Virgin Mary in 1858. The grotto is now a significant pilgrimage destination for millions of visitors each year. Inside the grotto, there is a spring that many believe has healing properties. The water from this spring is collected and used in various rituals and ceremonies. The site is also home to a statue of the Virgin Mary, which was placed there to commemorate the apparitions and to honor the religious significance of the location.