Just chanced upon this website
documentaryheaven.com
which has over 1700 documentaries available for video streaming. There's a huge selection with something that suits most tastes and according to the T&Cs of the site the source of these videos from public domain sources makes them kosha in terms of copyright issues.
Good broadband speed a must obviously.
Enjoy
Harm Less Solutions.co.nz
NZ & AU distributor of Eco Wood Treatment stains and Bambu Dru bamboo fabrics and clothing