Charco de los Clicos. Uploaded by Doblonaut. From Lanzarote, Canary Islands.
Yeah, alright, somebody is going to think that I chose the word "lava" because I've missed Iceland (it hasn't popped into the thriller list for at least a week). Well, maybe there's a grain of subliminal truth in that because an Icelandic pic did show up (what a surprise). But really, I had a hard time chosing between two pics above...so I am presenting them both. Interesting because they both show green volcanic lagoons. The bottom one is from the Canary islands.
The thought I had when I saw the Iceland pic (Glacierlake) was...what if the next Mars probe snaps a pic like this? Maybe they already have but from a long way away.