I just got the "Venture to the Volcano" mission today. However, when I click on "Quest", it brings me to the buildings tab - which is blank. There is nothing for me to build in order to finish this question. I'm assuming I have to build the quest building, but it's not there in the Buildings tab. And yes, I've tried rebooting my device, restarting the game, you name it. The building simply isn't there.