I stumbled across this Mail Art Tutorial on Ziggle Designs blog when I was looking for something to craft on the Scrap Orchard site. I was inspired and the video really helped me figure out what to do.
Here's the front of the envelope:
Here's the back of the envelope:
Once I had the envelope done, I needed a card to go in it. I decided to use the same art journal feel for the card. I remembered these nautical Magnolia stamps that I had in my stash and I thought they'd be perfect for the card.
The card and the envelope both have a hidden door: