The John Carter stories are about a Confederate cavalry officer searching for a rumored gold mine, pursued by Indians he runs into a cave ready to make his last stand but the Indians refuse to follow him inside. He falls asleep in the cave and wakes up on the dusty Martian plain.

This is an unbelievably action packed set of stories that has not a single boring page in any of the 5 or so books that it contains. John Carter jumps 100 feet in the air, kills a LOT of people and aliens, and rescues a princess (of course). Hes an actual gigachad who fights like John Wick with a sword, doesn't spend a single second on the implications of his ultraviolence, and never turns his back on an adventure or a friend in need. In these stories the women are womanly, the men are manly, the various races of Mars don't like each other and everyone gets mogged by the fighting man of Virginia. 
These are hot-blooded action stories for men. The romance is subtle, the feats are harrowing, the action is swashbuckling. The cover (pic related) is exactly what the story is like. What you see is what you get.

https://i.poastcdn.org/2b37b2615c34f8ebf15db0c1921a464f23ec9ee958df789db95d2db2b391abf0.jpg 

 Written in like 1916 btw 

 Ah, cave-kun, the true western way to isekai yourself.

That one comic about the Indios killing dinosaurs my father used to collect started the same way.

https://i.poastcdn.org/d26e30428d3498684051820f002477e09d83c921f4b0ac1acc1808a9b6fdccd6.jpg