Some of the most powerful telescopes in the world. From left to right, there's the Caltech Submillimetre Observatory, the James Clerk Maxwell Telescope, Subaru, the twin Kecks, and NASA's Infrared Telescope Facility. Note Mauna Kea's shadow off to the left.
This was taken from just outside UKIRT, and is a composite of three pictures (as I'm sure you can tell!).