One of the most useful resources for gaming in the classic era of the Mythos is the British Pathé YouTube channel. It's filled with hundreds of newsreels going all the way back to 1910, and dozens more are added every week. Over the company's long history it covered everything. Contemporary news events, the latest in period technology, exotic locales around the world, offbeat people and events...you name it, it's in there. The archives are a goldmine of research material.
As an example, here's their look at the flight of the Graf Zeppelin from Frederikshavn to Rio de Janeiro in 1932. Amazingly, the over 5000 mile journey took just four days to cover three continents. Is there any location more filled with adventuring potential than an airship in flight? The gentleman with the ear horn is just begging to become an NPC.