I saw thread and map postcard kits selling on Uncommon Goods and thought the idea would be super simple to make into larger art. I got my map image from here (and they got it from the free CIA maps). I played around with colors a bit (in Illustrator) and then printed it on cardstock with my inkjet. I made a list of trips that my husband and I have taken together, used Google maps to make sure I had the cities in the right places and then poked away with a large needle. For the thread, I used half the thickness of embroidery floss (3 strands). I just tied one knot on the back side, stitched from location to location and then tucked the remaining floss in the back of the frame to easily add future travels. I plan to continue charting our trips (we've been married less than a year, after all!) and I think I'll probably change floss colors next year, too.
We think it would be fun to try this with a world map, too. Happy travels!