To expand upon this, the kids create a matching book with a picture of their structure (and their written description complete with labels,etc). You could also use a story telling app--creating a digital book to document and write about their work.
Make a Book of World Structures for Your Block Center
Too bad we can't have a block center any longer. Create a photo book of famous structures from around the world to use in your block center. Great for kindergarten, preschool, and homeschool classrooms! Includes a link for a free structure book!