October in Peru is known as 'mes morado'-- the purple month, on account of the fact that fair Lima's streets literally turn purple, as the hundreds of thousands of purple-clad devotees of El Senor de Los Milagros file in procession in honor of that icon. The celebration peaks on October 18th, but expect the streets of Lima to be cloaked in that royal color for the duration of the month. Today, the Peruvian diaspora has brought the devotion to the Lord of Miracles to such far-flung areas as New York City (where a procession is held on 51st Street), Madrid, Australia, and even Japan.
From the Kleph blog, a history of the devotion to the Senor:
According to tradition, in 1651 a slave who had converted to Catholicism painted the depiction of Christ on the cross on the wall of a building in the outskirts of Lima where new devotees to the faith gathered to pray.
When a devastating earthquake struck the city four years later the entire building collapsed except for the wall adorned with the painting. Over the next several decades, the image became associated with miraculous incidents. More and more people, particularly the descendents of slaves, began to worship at the site.
This concerned both the church and Spanish authorities and, in 1671 the image was ordered destroyed. According to legend, workers were not able to do so. But, for whatever reason, officials eventually relented and built a proper church on the site – the church of Las Nazarenas.
When another huge earthquake struck Lima in 1687, the chapel was destroyed but, once again, the wall adorned with the painting remained standing. This cemented the importance of the image to the faithful and church leaders ordered a painting of the image to be taken out in procession that October – the tradition that continues to this day