WARNING THIS POST IS ONE, LONG OPEN SPOILER WARNING
Well, Dale Sams, now you’ve gone and done it; punishment for acknowledging my previous post is exposure, for everyone, to “Universe of the Vampires.” And BTW, where’s my bourbon? 
I’m 99.9% sure the title was “Universe…,” and not, “World…” IMdB has a “World…,” and this is definitely not that one, and since the title I know is wrong (or translated incorrectly), then I feel it belongs here. I’ll use the same format as before:
When did it come out? Saw it on TV circa 1970; it was B&W.
Who was in it? I 'unno; another Mexican vampire film.
What plot if any do you remember? Head Vampire has a castle on top of a mesa in the desert. Underneath the castle is a maze of caverns; in the middle is a deep pit with spikes in the bottom (pointing up, of course). Our Hero’s brother (?) is creeping around in there for some reason, and is captured by the teeming horde of vampires that inhabit the caverns and tied to a post near the pit. An aside–there are tarantulas crawling everywhere; these Ts are each the size of a dinner plate (real ones, too). At some point, HV gives the signal and the horde moves in and finishes off the brother. A little later, OH’s girlfriend is captured by the HV and taken to the caverns. OH sneaks in for the rescue, manages to fight off the entire horde somehow, and goes hand-to-hand with HV. After several minutes of furious battle, OH backs the HV up to the spike pit and HV falls in and is DOA. OH finds the GF, and as he leads her out, she realizes she has fallen in love with HV, sees him dead in the pit, and throws herself in. DA END.
What was special to you about it? It was the first movie I had ever seen that didn’t have a happy ending.
Any other clues you can think of? There must have been a batch of Mexican horror films released to TV at the same time, because it seems I saw a bunch of them over the course of one summer.
And that’s it! Any ETA on that bourbon? 