To experience avant-garde architecture, visit the northeastern part of the city where the event center built by Herzog & de Meuron forms the impressive terminus to Avinguda Diagonal and a gigantic photovoltaic pergola dwarfs anybody standing at its base. With its sloped surfaces, the expansive site is a mecca for skateboarders. The seawater pool, built for the recreation area of the Parc del Fòrum, is perfect for a swim.