[paw broon]

For all you superhero/masked mystery men/villains fans, there are many serials and films on youtube. 
The Phantom:-
https://www.youtube.com/watch?v=h-Jr3DOM5uc
The Adventures of Captain Marvel:-
https://www.youtube.com/watch?v=QSseP8A-S9s
Green Hornet:-
https://www.youtube.com/watch?v=le8LTjAOWIE
The Spider:-
https://www.youtube.com/watch?v=PkMUEfkTgcc
The Secret Code (with The Black commando):-
https://www.youtube.com/playlist?list=PLEuICzPiP8rIirnCIkMTN8B4MT7RzybEE
Spy Smasher:-
https://www.youtube.com/watch?v=lQhrlF8goDM
Mysterious Dr. Satan (The Copperhead):-
https://www.youtube.com/watch?v=5yQe1A9O6Oc
Blackhawk:-
https://www.youtube.com/watch?v=4swscHF9I8w
The Vigilante (Greg Sanders):-
https://www.youtube.com/playlist?list=PL0CqXHLa8uEQJpnfpOIX1GcW63AVmRUMr
Masked Marvel:-
https://www.youtube.com/watch?v=Ee9AtL0IgT8

Turkish cinema has 3Dev Adam with versions of Santo, Captain America and a nasty, villainous Spiderman.  An infamous film. Those of a nervous disposition, don't watch. Adult.
https://www.youtube.com/watch?v=9BlUYTqCqc0
More Turkish - The Pirate:-
https://www.youtube.com/watch?v=pC6lh6rSyHc
A version of Spy Smasher:-
https://www.youtube.com/watch?v=ZMMPEkgTM2g
The Masked Devil:-
https://www.youtube.com/watch?v=yxtPN1-bq6c

Italian - Argoman:-
https://www.youtube.com/watch?v=wU6_faz7Y54
Kriminal with very bad sound:-
https://www.youtube.com/watch?v=WW_tRjYjbpI
Turkish version of The Copperhead:-
https://www.youtube.com/watch?v=fETz9I-TmLY
One of the Turkish Phantom films:-
https://www.youtube.com/watch?v=HHmARzsK4Ks

Kilink - the incredibly popular Turkish villain of films and photocomics. Be warned - nasty.
https://www.youtube.com/watch?v=9BlUYTqCqc0
Many more..

[The Australian Panther]

John Wayne, early in his career made a few serials, not always the star.
Hurricane Express
https://www.youtube.com/watch?v=YRomHlBTV7I

Shadow of the Eagle (1932) | Complete Serial - All 12 Chapters | John Wayne
https://www.youtube.com/watch?v=CQ6XT3h5ypw

John Wayne Three Musketeers (1933)
https://www.youtube.com/watch?v=SzlXe2n92DI
[This is actually more like Beau Geste!

There were many western serials, including several Zorro stories.

Zorro Rides Again (1937) 12-CHAPTER CLIFFHANGER
https://www.youtube.com/watch?v=mz8ogS6btjs

There are also Flash Gordon and Dick Tracy serials.Don Winslow of the Navy and many more.
So, obviously, even then, Hollywood used comic properties - Comic Strips which ran in Newspapers and were hugely popular] to make movies.
There really is nothing new under the sun!   

Up to the time TV changed everything, when you went to the movies you got a cartoon, a serial, a B movie and then the main attraction. And screening went on continuously all day. So you could go in at any time and leave at any time. With intervals where girls with tray of drinks and ice- creams would wander round the theater.
When I was about 8, I was allowed to go to the movies on my own - small town - different times.
Don't remember the movie but the serial was
Deadwood Dick - Chapter 1     
https://www.youtube.com/watch?v=IdYBV0m2PRE
This is the iconic serial of them all.
THE PERILS OF PAULINE (1914) - ch.1 Pearl White
https://comicbookplus.com/forum/?action=post;topic=23093.0;last_msg=89160
Started the whole thing rolling.
Revived many times in many ways, not always successful.
Perils of Pauline (1933) | Complete Serial - All 12 Chapters | Evalyn Knapp
https://www.youtube.com/watch?v=ZVPQa-10030&list=PLjWddXHkjgZerflq18ursfs1y8gjgdOkr
This one is worth watching, great print! Not much of Pauline tho.
I also think Penelope Pitstop is the great granddaughter of Pauline! 
The Perils of Penelope Pitstop intro[Paul Lynde as the Villain.
https://www.youtube.com/watch?v=wJcXXAYxc90

This stuff is seriously corny, but great fun!