Watch the trailer for the new Kurt Cobain doc, see Obama read mean Tweets about himself, and more stuff you need to see today.
1) Watch this 90s-flashback-inducing trailer for Kurt Cobain: Montage of Heck
2) President Obama grins his way through some Mean Tweets on Jimmy Kimmel
3) Iron Man (a.k.a. Robert Downey Jr.) presents a kid in need with a real bionic arm
4) A 57-story skyscraper, built in 19 days—here’s a time-lapse look at the spectacle
5) Original Formula 1 exhaust pipes, repurposed into bespoke sound systems
Photo by Frank Micelotta/Getty Images.