Put a picture of the beach you visited in a shadow box frame and fill the bottom with sand from that beach. Much neater than a random jar of sand and shells! decorate the frame or put seashells or treasures found on the beach in the shadow box
(Hummm, neat idea, but uncertain on photos wrapping around the corner. The frames could meet up on the edge, but think the frames still might be best if they met in the corner but that each wall had its own photo frame.
DIY accordion-style travel scrapbook: take apart an out-of-date travelbook from a place you've visited and reassemble it using the front and back cover, a few pages, maps and memorabilia. Tutorial by Martha Stewart.