Not a true documentary (since it was released as a TV series in episodes), but I'd say The Long Way Round. It documents the real life journey by Ewan McGregor and Charlie Boorman as they attempt to road trip from London to New York on motorcycles (except for a plane from eastern Russia to Alaska).
They come across a number of different cultures and outdoor adventures along the way. It's very entertaining and an interesting look into different countries of the world.
I'm rarely hooked to TV shows, but this one got me.
Along the same lines. Without as much production/support behind them.
Sibirsky Extreme Trail( To map an offroad trail route all the way from the edge of the European Union, across Eurasia to the Pacific Ocean at Magadan)
https://www.youtube.com/watch?v=D_ZC2WPnkfc
They come across a number of different cultures and outdoor adventures along the way. It's very entertaining and an interesting look into different countries of the world.
I'm rarely hooked to TV shows, but this one got me.