Visit the co-cathedral to see two spectacular Caravaggio paintings
It was very crowded when we were there.
saw things this way
This was a surprising experience for us in that we did not expect it to be so interesting. There are many interesting historical sites and the co-cathedral is beautiful. But, it can be very crowded, and filled with tour groups. You do not need to book a tour to see the sites. Do some reading on your own before you visit Valetta and you can do much of it on a self-guided tour. The island of Gozo is also worth seeing. There I would suggest the Hop-on Hop-off bus. Also do not book the bus beforehand. It was cheaper just to do it when we got to the port of Gozo.