Wormhole

A slot canyon opening shaped like a portal, warm light pooling at the far end while the nearer walls fall into cool blue-lavender shadow. The warm-cool split does most of the work. Thirteen seconds at f/14 to hold detail through the whole depth of the passage, from the lit opening back to the dark foreground.

The dark is most of the frame, and that's on purpose. Almost everything close to the camera is in shadow, so the only bright thing in the picture is that pocket of orange at the far end. It reads like a way through to somewhere else. The rest of the walls catch just enough bounce to show their grain in blue and lavender before falling off into black.

We were standing in near-darkness the whole time. The opening is 50 or 60 feet above you, and the light that comes down gets absorbed by the walls on the way, bouncing and losing color until almost none of it reaches the sand at the bottom. You're in a cool blue trench looking at a warm glow you can't get to.