Stamps

I recently posted a blip of one of my dad's letters to my mom during WWII. 
Most of my dad's letters to my mom were mailed for free from US Army posts, but occasionally there are actual stamps on the envelopes. There is so much information on the envelopes with the postage stamp dates and various addresses. The stamps are iconic of the times. 
The letters that I am reading now are especially interesting. My mom is about to deliver my brother. She is in New York, and my dad is in Texas, training Army recruits.
My dad mentions (with surprise) that Memorial Day is not celebrated in Texas, but that Confederate Memorial Day is a Bank Holiday. I looked it up, and it seems like it is still a thing in some southern states.