Prepare a little talk about your city. You have a lot of information in English about Cartagena in the " Ayuntamiento de Cartagena" web page (below you have some links to it). CLICK ON THE BRITISH FLAG to read the information in English). These are some of the questions you have to answer:
Where is the best place to take a photo of the town?
What's the most interesting local festival?
LOCAL FESTIVALS
What's the most typical thing to eat?
GASTRONOMY
What's the most beautiful place near here to go on an excursion?
BEACHESNATURAL AREAS
Where is the best shopping area?
I'm looking forward to listening to you !