But there were no calendars for sale

At Mexic-Arte there's a traveling exhibit from the Museo Soumaya, with plenty of original oil paintings produced as graphics for calendars printed by Galas de Mexico. Of course there were Aztec warriors galore and many other originals of artwork still in use. There aren't that many visual examples to be found in a hurry, but there is an appreciation in the form of an academic paper. We've never thrown one out. Sometimes you get a choice and sometimes you don't. Some are gifts outright and others are acquired for a dollar or so.