Song of the Swallows, Leo politi's most famous book and winner of the 1952 Caldecott Medal is definitely still easy to come by since it is still in print. The book is set at the Misssion San Juan de Capistrano in southern California. The anniversary of the founding of this mission is in November (1st - sorry to let it pass so long).
San Juan Capistrano was founded November 1, 1776 by Father Junipero Serra. This was in fact the second founding. Originally Father Lasuen founded the mission on October 30, 1775 but the site was quickly abandoned after only eight days following an devastating attack on Mission San Diego. The bells were buried and the padres fled to the safety of the Presidio in San Diego. Father Junipero Serra returned a year later and retrieved the bells and reestablished the mission.
This month would be a nice to time to study a little on the mission foundings in the United States. Maureen Wittmann has an expcellent unit study for the missions following this book.
Add in Politi's The Mission Bell for even more information on mission founder, Junipero Serra.