Mentioned by edinburgh.org
17 Free things to do in Edinburgh - Forever Edinburgh
"With four levels of exhibits featuring everything from the natural world, world cultures, science & technology to art, design & fashion and Scottish history, a trip to The National Museum of Scotland offers a whole world of discovery for all the family. Start your visit in the beautiful Grand Gallery and marvel at the massive skull of Moby the whale; travel back in time as you explore the Scottish galleries; or why not explore centuries of creativity and innovation in the Fashion and Style gallery – whatever your interests, you’re bound to find something in this awe-inspiring museum to capture your imagination. Free entry, advance online booking required."