Dique de Levante Breakwater is a main tourist attraction in Torrevieja. It's a nice 1,6 km walk to the lighthouse, you can bring along something to drink and there are nice pergolas for sitting down for a moment.
Near the Breakwater there's a great fairground with rides for both adults and children. The fun-fair opens at about 8 PM in the summer.
There's also market stalls near the Breakwater selling jewellery, T-shirts, toys and tourist nick-nacks.