The Walking Dead 5.09: "What Happened and What's Going On" (2015) directed by Greg Nicotero
Interesting mid-season opening, with the majority of the episode dedicated to Tyreese's dying delusions. Somber in tone to match the character's exhaustion with the world they're forced to live in, the episode was also edited a little more arty than normal. I liked it. Though, personally, I think they should've re-sealed the wall and tried to build a community in that place. I'm guessing the trip to Washington will be as successful as the trip to the CDC in season 1.
My favorite bit was Tyreese's imagined BBC Radio report from when the zombie crisis first began (with the announcer voiced by Andrew Lincoln in his native accent, no less). I wish we'd get more glimpses into the time period when Rick was in his coma (but maybe that's what the spin-off show is about? I haven't paid attention).