Here's an unusual card from 1907. On the front of the card is a little teensy envelope, and inside that card is a little message. Both are shown here.
The card is embossed as well, which you can see better when you look at the address side of the card, as opposed to the front. Double click on any of the images, and you'll be able to see the beautiful detail better.
It's Postcard Friendship Friday, so if you get a chance, check out some of the other postcard blogs by clicking here.