1. Park Güell: Explore the whimsical architecture of Antoni Gaudí and enjoy panoramic views of the city from this iconic park.

2. La Rambla: Take a leisurely stroll down Barcelona's most famous street, lined with shops, cafes, street performers, and vibrant atmosphere.

3. Barceloneta Beach: Relax and soak up the sun on this popular beach, located just a short distance from the city center.

4. Gothic Quarter: Wander through narrow cobblestone streets and discover medieval architecture, charming squares, and hidden gems.

5. Casa Batlló: Admire the stunning exterior of this modernist building designed by Gaudí, a true masterpiece of architecture.

6. Montjuïc: Explore this hilltop area, home to attractions such as the Magic Fountain, Montjuïc Castle, and incredible city views.

7. Mercat de Sant Josep de la Boqueria: Immerse yourself in the vibrant atmosphere of this bustling market, offering a wide variety of fresh produce, local delicacies, and more.

8. Parc de la Ciutadella: Enjoy a peaceful escape in this green oasis, perfect for picnics, strolls, and boat rides on the lake.

9. Cathedral of Barcelona: Visit this impressive Gothic cathedral, known for its stunning architecture, serene courtyards, and breathtaking views from the rooftop.

10. Museu Picasso: Discover the extensive collection of one of the world's most renowned artists, housed in several medieval palaces.

Please note that some attractions may have optional paid features or special exhibitions. It is always recommended to check the official websites or visitor information for the latest updates.