What are the best documentaries on YouTube?

This Is The Zodiac Speaking is a documentary which covers every aspect of the Zodiac investigation that includes interviews with the original investigators and surviving victims. 

Weed is an award-winning CNN documentary by chief medical correspondent Dr. Sanjay Gupta who goes trough the scientific reasoning around the use of cannabis for medical purpose. It's a must-see documentary full of scientific research and real experiences.

Quantum Theory is a free documentary posted on YouTube which focuses on quantum mechanics (QM), also known as quantum physics, or quantum theory, a branch of physics which deals with physical phenomena at nanoscopic scales. 

SHELTER is a one-hour documentary video uploaded on YouTube by VICE which followed the lives of homeless youths in New Orleans for a year. This comes as the chronic homelessness in America is on the rise. 

Alone In The Wild is a video, which is a part of 2009 documentary television series Alone In The Wild, posted on the YouTube channel of digitalsc4rz. This follows the adventures of cameraman Ed Wardle. 

Real Stories is a YouTube channel which uploads at least four full-length documentaries every week, as well as multiple video clips showing the most fascinating insights into the real life.

VPRO Documentary is a YouTube channel which uploads new French and Spanish subtitled documentary each week about current affairs, finance, sustainability, climate change or politics. The videos are co-funded by the EU. 

Planet Doc is a YouTube channel which is about full documentaries where you will be taken on a journey around the planet to help you learn and get to know the most amazing creatures, cultures, and traditions.  

Documentary Heaven is a website with a big database of documentaries you can watch online for free. They are classified by genres, so anytime you want to feed your brain you'll find something interesting to watch.

Superb Documentaries is a YouTube channel which provides a good selection of documentaries about nature, culture, history and the society. This particularly focuses on documentaries about India. 

Down the Rabbit Hole We Go! is an article published on DIY Genius which provides a list of mind-expanding documentaries from different viewpoints, controversial opinions, and even contradictory ideas.

Storyville Silk Road Drugs, Death and the Dark Web Documentary 2017 is a documentary that looks at the black market website known as the Silk Road, which emerged on the darknet in 2011. This 'Amazon of illegal drugs' was the brainchild of a mysterious, libertarian intellectual operating under the avatar The Dread Pirate Roberts. Promising its users complete anonymity and total freedom from government regulation or scrutiny, Silk Road became a million-dollar digital drugs cartel.

*NO LONGER AVAILABLE*

YouTube Videos to Learn From is an article published on LearnOutLoud.com which provides a collection of educational documentaries from PBS including series like Frontline, American Experience, NOVA, and more. 

Here's a bunch of Documentaries you can watch on YouTube is an article published on Imgur written by TotalSmartAss which provides a number of interesting free documentaries about nature, science, people and history.

21 Best True Crime Documentaries You Can Watch on YouTube is an article published on CrimeViral.com which talks about documentaries tackling the most disturbing and mysterious crimes to have happened over the past fifty years.

Capturing The Friedmans is a documentary film released in 2003 which is about the 1980s investigation of Arnold and Jesse Friedman for child molestation. It will take us on the circumstances following the arrest of the two.