1. Barcelona: Known for its stunning architecture, including the Sagrada Familia by Antoni Gaudí, as well as its vibrant cultural scene, lively markets, and beautiful beaches.
2. Madrid: Spain's capital city offers a blend of historical sites, such as the Royal Palace and Plaza Mayor, with modern attractions like the Reina Sofia Museum and Retiro Park.
3. Seville: A city with a rich cultural heritage and stunning Moorish architecture, including the Alcázar palace and Seville Cathedral.
4. Granada: Home to the Alhambra, a UNESCO World Heritage Site and one of the finest examples of Islamic architecture in the world.
5. San Sebastián: A coastal city renowned for its beautiful beaches, seafood cuisine, and annual film festival.
6. Valencia: Known for its futuristic City of Arts and Sciences, as well as its historic city center with Silk Exchange and Central Market.
7. Córdoba: A city with a rich history and cultural heritage, featuring the Great Mosque of Córdoba (Mezquita) and Jewish Quarter.
8. Santiago de Compostela: A popular pilgrimage destination, known for its beautiful cathedral and historic city center.
9. Ibizad and Mallorca: Balearic Islands that are famous for their stunning beaches and vibrant party scenes, as well as charming historical towns.
10. Salamanca: A university city with a beautiful old town, sandstone buildings, and a lively atmosphere.
These are just a few of the many incredible destinations that Spain has to offer. The best place to see depends on your interests and preferences, and you may want to consider factors such as weather, time of year, and what types of experiences you are seeking.