It’s the scale of this image that blows my mind. Those are crystals, the largest in the world.
This is not SF. It’s the Naica mine in Chihuahua, Mexico. The mine supplies lead, zinc and silver and these gigantic crystals are something the geology has thrown up, a result of hydrothermal fluids emanating from the magma chambers below. The crystal cavern is a thousand feet below the surface, and the temperature in the cavern is 58°C (136° F), and the humidity is so high, no one can enter the cave without environment suits and breathing apparatus.
So I guess it is an alien landscape, after all…