Timeline World War 2 ($8.99 promotional launch price) offers an amazing experience that allows you to explore history along an interactive timeline. With it, you can track events, view newsreels, see maps evolve over time, and more. It's a groundbreaking application in that it fully realizes the museum experience, providing a nuanced exploration of a huge amount of data.
Weighing in at 0.75 GB, it's a massive iPad app, but it is jam-packed with material.
The primary timeline view tracks history from September 1939 all the way up to September 1945. Its month-by-month timeline layout includes layer after layer of artifacts, with embedded photos, videos, letters, overview cards, and more. You can dive into dates and events, zooming in and out of detail.
A secondary map view shows the physical progression of war events for both the European and Pacific theaters. I can't emphasize how much maps matter in understanding these kinds of stories -- and it's a great pleasure to see that show up as a key presentation. You can drag a timeline slider at the top of the map to view the maps at any time in the same 1939/1945 range.
A video introduction presented by Robert MacNeil launches you into the app, and from there it's quite straightforward to navigate through the presentations and material. There's so much there there, however, that you may get overwhelmed. It's probably best to browse, taking enjoyment in the serendipity of found experience.
I'm not sure that Timeline World War 2 will stay on my iPad on the long term. It's really huge (I own a 16 GB unit) and my interest in WWII is limited. But for any fan of the History Channel-style documentaries, this is sure to be a perfect gift or self indulgence. It's beautiful, it's expansive, and it's a great demonstration of what the iPad can do at its best.