Do you have any paperwork? Perhaps you can get it back someday. The tenants don’t own it and there will be no place for them to move to except perhaps Miami.
I don't have any official paperwork, but they most certainly do. The Cuban bureaucracy is not capable or willing to produce it, so I wouldn't even bother as it stands now.
If it were given to me I'm not sure I would even want it. The structure has amazing architectural "bones" so to speak, but the roof has been gone for decades and the interior is nearly completely destroyed.
Even if they allowed investment and I was able to renovate it (which would be a HUGE and expensive challenge), what once was a beautiful thriving neighborhood is now a slum... so there's that.