What's the longest video you've ever watched from start to finish?

[Sunstone]

Got this idea thanks to @Dozle The Crusader and him listening to very long loops of Girls und Panzer music. xP

For me, I'm not sure if I know the specific longest video that I've ever watched in its entirety, but I have watched some long videos before. o.o I reckon if I had to make an educated guess on what the longest video is that I've ever watched back to front, it might be a Longplay video - something like a part to a Final Fantasy Longplay which I watched from start to finish as a challenge years ago. I remember watching this whole series, which has every part clocking in at just over 4 hours long.
 

Another candidate would be, funny enough, the (former) "world's longest song". I listened to this back in 2017 as a dare, and won! I'm glad I won it, because I genuinely think it's a good song that was worth listening to. ^^ Especially at 10:00 - 24:30, and 1:14:40 - 1:29:40. Gives me chills...  
 

So... how about you all? What's the longest video you've ever watched from start to finish?  

[Dozle The Crusader]

all 10 hours im on my 2nd run with it & hours and a half XD 

[Sunstone]

Just now, Dozle The Crusader said:

all 10 hours im on my 2nd run with it & hours and a half XD 

Mad Lad.

[Dozle The Crusader]

for motherland 

[Elena Ichinomiya]

 

Watching this in 1.25x speed. Somewhat satisfying. Sadly the player seems new on this type of action game...

The other is Silent Hill 4 walkthrough back in 2008. Its 1 hour each part with 32 hours in total (it has 32 parts)