For those who already have these buildings fully evolved... even more of a bummer. I'm on both sides of this. In one city, I have them all at L10. In another, I have none of the older ones, though I got very lucky and won enough artifacts to place a Fire Phoenix. In the end, I'm happy that I and others are getting an opportunity to evolve these buildings, even if it means 1 useless Spire prize for me in one of my cities. I still think the Spire rewards are worth the effort every week.So, what's the deal with getting extra artifacts for these evolving buildings? In 8 cities where I climb the whole spire every week I managed to get enough artifacts for one level 7 Stonehenge with all others at 2-4 artifacts. Mermaids is shaping up to be the same. If they just keep cycling it will be next year before I get enough artifacts to complete any evolving building. That's a year of no main prize worth anything to me.