Valletta is one of the smallest capital cities, it's about 1000m long by about 400m wide, and is on a peninsula sticking into the largest harbour in the Mediterranean. It's surrounded by water on three sides, and the final part is very well fortified with thick walls and deep ditches.
All of the buildings in Valletta are made from limestone, so there's a very Mediterranean feel to the place, but there's also a Mark and Spencers, British Post and Phone boxes, and quaint shop fronts with elegant sign writing from the 1930's. It's a very strange mix, but a very nice one!
Valletta boasts one of the oldest wooden theatres in the world, it dates back to the 1700's and the interior is intact and original. It's well worth taking the guided tour if you get the chance.
Valletta has a commanding view over two huge harbours, so there are few places you can go that don't offer tantalizing views of the water.