I shot with Tala Artmodel during an extended 1:1 workshop I conducted in June, and shot all these within 5 minutes.
It's the entrance to a bunker on the derelict airfield, and it's all natural light.
It might be worth mentioning that was why I went there. The walls work as a sort of tunnel of light, coming straight behind the camera, as if it had used a very large ringflash, and blocked the bottom part (the ground when talking about natural light).
One of my principles when I'm talking about light is this:
I don't care where the light is coming from (except not from below), but I care about the angle it strikes the body (usually it's best if it's partly from the side, as in all these) and therefore how it interacts with the model's body in regard to highlights and shadows.
In this case, we had Kayla apply an ample amount of oil to create the specular highlights that make her stand out so clearly.