Info from Official Mafia Wars Blog:
With the Neo-Imperium distracted by their criminal activities in other parts of the world, your chance has come to sneak back into Cuba. Your job progress will start for where you left off, but you’ll find a new tier of job mastery and powerful new loot. Be sure to hurry though, the Neo-Imperium won’t be fooled for long. Grab what you can while you can, because this temporary visa won’t last forever.
Cuba Event Developer Explanation: Due to player request, we will be re-opening Cuba temporarily for 2 weeks. Many players are disappointed that they no longer have access to Cuba job progress and properties, so we wanted to attempt a temporary re-opening through a limited time event to see how players enjoy it.
During this time users will have access to Cuba with new added loot drops. Their job progress will be the same as when they left it. Additionally, for those players who already finished Cuba, we are releasing a Ruby tier of Job Mastery. We are very aware of the dedication players have put into finishing Cuba, so we wanted to make sure everyone has something to tackle in the re-opening, along with high end loot drops and new mastery items for completing Ruby Tiers.
We would really like to hear your feedback on this event, the Cuba shutdown event, and future city releases and events. We strive to make sure the new city content we release is the best for our players that it can be! Thanks everyone – and good luck dealing with the Neo-Imperium!