The catacombs of St. Paul and St. Agatha are an interesting place to visit in Rabat. The catacombs were used in Roman times to bury the dead and later by the early Christians as a secret meeting place and holding their mass. The catacombs were named after St. Paul (probably before he became a saint) was shipwrecked in Malta in 60 C.E. and stayed on the island for three months, either for a vacation or because it took him that long to find another ship. I don't know who Agatha was, my guess is that she might have been Paul's girl-friend whom he met during his 3-month vacation in Malta. Although all this might be pure speculation.
If you're into underground activities like me, you'll enjoy the mysterious atmosphere of the catacombs and their history as well.
Electricity in Malta has 220 Volt, but the plug might be different from the one that you use in your homecountry and so it will be the best to take an adaptor-plug with you, because even the big hotels obviously dont have a single plug in the rooms for the ordinary plugs of Europe.
Charging your batteries etc. will only be possible when you have the right adaptor like in my photo