Visit the bell tower and ossiary (bones) chapel. This is apparantly not in any guidebook because it only started this year. You can climb the tower ( about 3 stories high , not too steep) and get a lovely view over the old town, the river and the 'big' beach. You can also climb up anouther flight of steps to the actual bell tower which is an experience - be warned the bells chime every 15 mins and its loud up there !! You can then visit the small ossiary where there are skulls and bones set in the walls and ceiling.  There is also a small room with religeous artifacts. Getting  up close to the lovely old Church is also atmospheric.  It cost 2 euros a head - well worth it. Tickets available from a ticket seller in front of the Church. It is open 10 -1 and 4-6 as far as I recall. You can get to the Church by heading uphill in the old town, or go  the fishmarket and get the lift to the top floor ( nice views) and walk out of the back of the building onto the street . The Church is to the right.