We have the "Usborne illustrated Atlas of World History" which doesn't look as "babyish" as the one you asked about. I'm not sure why they call it an "Atlas". It has more pictures than maps. It doesn't go into a ton of detail and it's not a thick book, but it's written probably at a 6th grade level. Just as an example, it has about 12 paragraphs written about the "Mongols" on two pages, complete with several pictures of people and buildings and a bunch of small maps, as well as a timeline of events.
