For a smooth Spain trip, here’s a simple plan: Madrid (2–3 days): Prado Museum, Royal Palace, Retiro Park, and tapas in local cafés. Optional day trip to Toledo or Segovia. Seville (2 days): Alcázar, Plaza de España, Santa Cruz quarter, and a Flamenco show. Granada (1–2 days): Alhambra, Generalife Gardens, and Albaicín neighborhood. Barcelona (2–3 days): Sagrada Familia, Park Güell, Gothic Quarter, and Barceloneta Beach. For comfortable, convenient, and homely stays across these cities, www.thesqua.re serviced apartments are a great option.