u/Usual_Farm7617 and u/SiriusFoot already posted my favorite YouTube docs, but if you want a wider selection you can check out https://topdocumentaryfilms.com/. It is a collection of free documentaries on a wide variety of topics. Somehow I still like those YouTube channels better, but its a good site to bookmark. Source: about 1 year ago

• Documentaries:(Find mostly on Hulu, Netflix, or Youtube). Fairly comprehensive list can be found here: http://topdocumentaryfilms.com and archive.org. Source: over 1 year ago

I don't have any off the top of my head but check out this site. Source: over 1 year ago

Topdocumentaryfilms.com you can watch the best documentaries here. Source: about 2 years ago

• Documentaries:(Find mostly on Hulu, Netflix, or Youtube). Fairly comprehensive list can be found here: http://topdocumentaryfilms.com and archive.org. Source: over 2 years ago

I highly suggest checking out Natural Atlas (https://naturalatlas.com/) by the same small team who made the CoTrex app (https://trails.colorado.gov/) for Colorado Parks and Wildflife. A really fantastic team building some absolutely gorgeous topographic basemaps from publicly available data. Hopefully they'll find time to add a slope angle overlay at some point. - Source: Hacker News / over 1 year ago

I highly suggest Natural Atlas. The cartography is impeccable and they’ve been adding features over the last year. Source: almost 2 years ago

Try a recreational-themed map like naturalatlas.com. They will list most all known trails. Source: about 3 years ago