Wednesday is the feast of Our Lady of Guadalupe, the day that brings the most pilgrims to the site, located in Mexico's mountain capital. But the four-day span between Dec. 8 -- feast of the Immaculate Conception -- and Dec. 12 traditionally brings overflowing crowds.
This Dec. 12 commemorates the 476th anniversary of the last of the apparitions of the Virgin Mary to Juan Diego. Juan Diego was canonized by Pope John Paul II in 2002.
Each year between 18 - 20 million pilgrims visit the basilica, making it Christianity's most visited sanctuary and one of the most visited pilgrimage sites in the world. There are days on which the basilica is visited by up to 120,000 people.
The caretakers at the basilica expect that all attendance records will be broken this year with the arrival of 7 million visitors in only four days -- 2 million pilgrims are expected Wednesday.