The beloved Mont Saint Michel was scheduled to depart Second Life last month, but for one reason or another, it's still there -- I just briefly visited. Maybe the Japanese owner Moeka kohime hasn't transferred the sim yet, or the new owner hasn't wiped the actual build, or (as sometimes is the case), Linden Lab hasn't gotten around to taking it off the grid yet. Am looking into this, but in any case, click here to visit while you can.
That aside, there's some decent machinima memorializing Mont Saint Michel, which will lost forever (unless the heat death of the universe wipes out YouTube's servers, at least). Here's a new one from Kawanishi Yana: