Koyaanisqatsi, while not a traditional documentary, is a truly fascinating time capsule featuring a great soundtrack from Phillip Glass. It's all images/video with no dialog or voiceover. It's a unique experience (especially in an altered state of mind)
This isn’t so much a documentary as it is a video blog, but it’s so worth it.
Recorded back in the late 1960s it is a self documented story of one man moving to remote Alaska and building a cabin/homestead in that untamed wilderness.
I cannot recommend this enough. It’s thoughtful, peaceful, and heartwarming.
‘It argues that governments, financiers, and technological utopians have, since the 1970s, given up on the complex “real world” and built a simpler “fake world” run by corporations and kept stable by politicians.’
I recently watched, "Russia 1985–1999: TraumaZone" and greatly enjoyed it.
It's about what it was like to live in the Soviet Union at the end of communism and then the end of democracy. The story is entirely told with footage from the time.
I'd like to also recommend my two favorite documentaries about labor unions, Harlan County, USA and American Dream.
Dirty Wars is a 2013 American documentary film about American foreign policies and war crimes. It was the first time that I heard about their manipulations, wars and assassinations.
Closer to the Edge - Available on youtube for free, and is a glimpse inside the madness of the Isle of Man TT. I am not a huge fan of motorsports, but this is a fantastic and epic watch that follows a bunch of rides in the run up and through the TT.
Dark Side of the Moon
It seems like it is about how the moon landing was faked .. watch until the end because it is actually about something much more important
I'm surprised not to see this one anywhere on the list:
Planet Earth
And I saw one recommendation, and want to second:
Free Solo
Planet Earth is just an absolutely stunning visual spectacle showcasing nature at it's most beautiful. And Free Solo had me glued to my seat like no other documentary that I've ever watched. Alex Honnold's brain is just wired differently, so he has no fear rock climbing without a harness or a rope up an insanely difficult vertical climb of El Capitan.