St John’s Co-Cathedral is Valletta’s must-see, and the interior does something the plain limestone exterior gives no hint of — wall-to-wall baroque decoration, gilded stone carved directly into the walls and ceiling, and Caravaggio’s The Beheading of Saint John the Baptist hanging in the Oratory, the only painting he ever signed. It was built by the Knights of St John in the 16th century and decorated over decades to rival anything in Rome, and it’s easy to spend an hour inside without noticing the time pass. The marble floor is itself worth studying — inlaid tombstones for hundreds of knights, each one different. Go early on a weekday if you can, since the cathedral gets busy with visitors and cruise groups by mid-morning, and the crowds change the experience of a space built for quiet grandeur. Modest dress is required — shoulders and knees covered — and photography rules apply inside, so check before you go. It’s a short walk from almost anywhere in Valletta, making it easy to pair with the rest of the city’s sights in the same morning. Whatever else is on your Valletta list, this belongs at the top of it.
