In the culture and practice of the Roman Catholic Church - a Shrine to the Virgin Mary (or Marian shrine) is a shrine marking an apparition or other miracle ascribed to the Blessed Virgin Mary, or a site on which is centered a historically strong Marian devotion. Such locales are often the destination of pilgrimages.
Some of the largest shrines are due to reported Marian apparitions to young and simple people on remote hilltops that had hardly been heard of prior to the reported apparition. The case of Saint Juan Diego's reported vision of Our Lady of Guadalupe in 1531 is similar to the case of Saint Bernadette Soubirous's vision in 1858 of Our Lady of Lourdes. Both saints reported a miraculous Lady on a hilltop who asked them to request that the local priests build a chapel at the site of the vision. Both visions included a reference to roses and led to large churches being built at the sites. Like Our Lady of Guadalupe in Mexico, Our Lady of Lourdes is a major Catholic symbol in France. Both visionaries were eventually declared saints.
The number of pilgrims who visit some of these shrines every year can be significant. E.g. Lourdes with a population of around 15,000 people, receives about 5,000,000 pilgrims every year and within France only Paris has more hotel rooms than Lourdes. Over 1,000,000 pilgrims visit the Black Madonna statue in the Chapel of Grace in Altötting, Germany every year, where for more than 500 years miracles have been attributed to praying to the Virgin Mary at that shrine.