One must not miss the opportunity to explore the architectural marvel that is La Sagrada Familia in Barcelona, Spain. This iconic landmark designed by Antoni Gaudí is a testament to his visionary genius. Marvel at the intricate details and towering spires of this unfinished basilica, which offers breathtaking panoramic views from its towers. Immerse yourself in the history and artistry of the structure by visiting the museum on-site. Don't forget to take a leisurely stroll through the nearby Park Güell or indulge in some delicious tapas at the local eateries.