The document provides information on several important landmarks in Barcelona's historic Gothic Quarter and Ciutat Vella area. It describes Palau de la Música, a modernist auditorium housing the oldest Catalan choir. It also discusses the Gothic church of Santa Maria del Mar and its simple exterior featuring horizontal lines and bare surfaces. Additionally, it mentions Plaça Sant Jaume, the political center since Roman times housing the Catalan government buildings, and the Gothic Cathedral of Santa Eulalia dedicated to the city's co-patron saint.