While former NSA contractor Edward Snowden's documents were being covered by news outlets worldwide, journalist Laura Poitras was also working on a documentary about the story behind them — from the first anonymous emails she received from Snowden, through the meeting in Hong Kong that would launch some of the biggest news stories of the past year. Called Citizenfour, it's premiering tonight at the New York Film Festival, in advance of its wider release on October 24th. We'll have impressions from the film and a panel with Poitras soon, but for now, you can see the trailer above. We'll warn you, it's not a particularly satisfying trailer, but you can watch it nonetheless. Or you could read a longform account of the meeting, published in The New York Times last year.