All the main characters at some point walk backwards. According to John Fell Ryan, the front and back halves of the film are symmetrical. Anyone walking backwards is matched by them walking forwards.
(Source: joaquinrafael)

I made this and I won’t apologize.
“She is by far the most committed, dedicated, focused actor i have ever worked with. a year before we started making the movie, on her own dime for 365 days she trained for eight hours, swam a mile a day, learned ballet, became a prima ballerina, and then when we shot, every single day she was in every single scene in every shot, and she shared her heart, soul and spirit with me and with the world.”
- Darren Aronofsky on working with Natalie Portman for Black Swan.

Lightning slowed down at 10,000 frames per second.
That is one of the coolest things I’ve ever seen
that’s crazy