The Nordic Optical Telscope, which I used for many of these images, is located close to edge of a crater on La Palma, a so-called caldera.
La Palma is geologically quite young, starting to rise from the ocean only a few million years ago.
But it rose too fast…
Eventually, the mountain started to crumble under its own weight, forming the 10 km large, and up to 2 km deep, caldera crater.
This picture is taken in the evening before an observing run, as the clouds come rolling over the opposite edge of the crater.