Barcelona, the cosmopolitan capital of Spain’s Catalonia region, is defined by quirky art and architecture, imaginative food and vibrant street life. It has medieval roots, seen in the mazelike Gothic Quarter, but a modernist personality represented by architect Antoni Gaudí’s fantastical Sagrada Família church. Its restaurant scene, anchored by the central Boqueria market, ranges from fine dining to tiny tapas bars. It was the city where we started our cruise.