blodbranddod

5€ to enter. There is a museum with prehistoric remains, religious paintings and objects as well as minerals and gems. Then you go into the catacombs with a guided tour. They are smaller than St Paul's but there are beautiful frescoes and skeletons.
I suggest visiting both St Paul's and St Agatha's catacombs.

Historic place with great view. Only 2€ to enter. 10mins walk from the bus stop. It's a must