I might be seeing this at zero hour just for the preview. I must say that my obsession of Nolan movies is borderline unhealthy. Because I was really looking forward to Suicide Squad and now this is why I want to see it ASAP.
For what it's worth, the trailer itself will likely be online before it's technically in theaters w/ SS. My guess is sometime Wednesday or Thursday morning.
For comparison, here are all of Nolan's teasers / "announcement trailers" that debuted roughly a year out from their respective film's releases, as will be the case with the teaser for Dunkirk, which clocks in at 1:06. The teasers for Batman Begins, The Dark Knight and Inception are the closest in runtime to Dunkirk's, so, point is, don't expect a lot of footage this go around...
Rumor is the trailer will be online either around noon central today or closer to six. No one knows for sure, but those are the times WB usually drops trailers online.
That final shot was AWESOME... one look, then another, then 3 others, then everyone. That is how you trailer tease. I know nothing about this movie(other than presumed setting) and I want to see it already.