Everybody knows about dropping into the lava at that fire elemental boss and swimming up the river for an easy un-attuned Molten Core entrance, or talking to the Blood-elf if you are attuned, but when exactly did the developers put a green raid portal here for?
Now that I notice, the coordinates for this mystery portal to Molten Core happens to match up perfectly with the position on the map but I always though that was the Blood-elf that portals you there. Why would you need a portal in the lava directly below somebody who teleports you there?
Edit: Sorry I couldn't get a screenshot of the raid portal, I managed to see it upon falling to my Dc-death when I couldn't be bothered with offline mode. I tried offline mode around 5 mins ago and it's an incredibly fiddly camera and angle to see anything.