After arriving in Mexico City, Amira and I noticed from the cab great herds of people all walking in the same direction. Turns out that we arrived on the peak day of Día de la Virgen de Guadalupe!
On December 9, 1531, a native Mexican named Juan Diego said he saw the Virgin Mary appear on Tepaeyac Hill in the city. Yada yada yada, now 9 million Mexicans walk, sometimes great distances, sometimes crawling or on their knees, to said hill to pay respects to the Virgen de Guadalupe.
So naturally we joined the throngs. (We were literally the only Americans we saw, other than a group of what I assume were Hawaiians.)