I really enjoy the Kurzgesagt videos. Its a great Youtube channel where they go to some of the most complex scientific topics and break them down in nice and fun way. Their cartoons like style is awesome and the videos are extremely well produced. They do a great research and reading when producing the videos and they are full with facts.
In my opinion is one of the best youtube channels. They have a bit more than 10 millions followers and deserve much more.
Here are some of my favorite videos.
What Are You?
The Origin of Consciousness – How Unaware Things Became Aware
What Happened Before History? Human Origins
Time: The History & Future of Everything – Remastered
Why Beautiful Things Make us Happy – Beauty Explained
The most recent one