On the southern edge of Gila County, snuggled into a valley surrounded by in the mountains, there is a town called Christmas. Now, the town of Christmas is a ghost town, but in the 1930s it had about 1,000 residents and a very popular post office.While people from all over the world would visit the post office to get the highly desired postmark at the holidays, the residents of Christmas lived there because of the copper mining.In this week's episode of Valley 101, a podcast from The Arizona Republic and azcentral.com, we are joined by retired geologist David Briggs to tell you the history of the Christmas mine and the coveted post office in its town. Learn more about your ad choices. Visit megaphone.fm/adchoices