Why not just leave it? Drones could protect it but even if we take the drones, worst that might happen is a bunch of squatters moving in who'll clear out the second someone with guns says it's their place now.
Or someone else blows it up, in which case we don't have to wonder what to do with it, eh?

LJ might be right that after taking out the other people who know about it, it might be safe; but that's a long term thing, if it'll even happen at all.