Documentary recommendations?

I know that there's Tiger King out there, I just haven't gotten to it.
And just to put my money where my mouth is, here's a recommendation from me:

They Shall Not Grow Old - (2018)

A WW1 documentary by Peter Jackson that only uses interviews from veterans and actual footage from the war.
The movie follows England's side in the war and the young men that enlisted. Around the beginning of the second act, they switch up the style of the documentary that truly made this an engaging experience. Go check it out!