Here's a classic Etruscan vase sunrise, taken from Flinders Beach on North Stradbroke Island last week. This effect is due to an inferior mirage caused by a layer of warm air just above to water. More on Flickr if you're interested.
Thanks very much guys! There could have been a brief green flash just before I took the first photo, because I didn't have the cable release in my hand when the sun first appeared, so there was a bit of a delay. I think the green flash would be easier to capture at sunset rather than sunrise?
