The Co-Cathedral is one of Maltas real gems. The external architecture is quite simple, but in a pleasing sort of way, and it gives you no clue about what lies inside.
If you visit Valletta you must be sure to come on a day when you can get into the co-cathedral because if you miss it then you are really missing out.
The whole of the interior is a monument to the power, splendour and exuberance of the knights. The intricacy of the carved walls & vaulting and the marble tombstones on the floor are quite unlike anything I've ever seen before.
Favorite thing: Enter the Co-Cathedral of Saint Johann. Nothing really special as far as the exterior is concerned, but splendid from inside - in baroque. Here knights were buried, and the chapels are of great interest. At the side the Museum of Caravaggio is situated.
Favorite thing: Valletta: The town was built at the end of the 16th century by the Knights of St John as the island's new capital and, more importantly, as a fortress commanding an impregnable position over the peninsula. The city developed around what is now Republic Street, Old Bakery Street and Merchants Street, the latter containing some of the finest examples of Maltese-style Baroque architecture in the islands. The Co-Cathedral of St John has an austere exterior, but the interior is a sumptuous mixture of gilded tracery, marble mosaic floors and a lapis lazuli altar behind which is a remarkable marble group of the Baptism of Christ. The painting by Caravaggio of the beheading of St John is in the Oratory.