Barcelona, Spain

Barcelona is the only city in the world to be awarded the Royal Gold Medal for architecture by the Royal Institute of British Architects (RIBA) – not to an individual architect, but to the city itself, in 1999.

The city's famous Eixample district, with its grid-like streets and chamfered blocks, was designed by urban planner Ildefons Cerdà in the mid-19th century to improve public health and transport, as the old city was plagued by overcrowding and disease.

Barcelona is home to the largest metropolitan park in the world, the Parc Natural de la Serra de Collserola, covering over 8,000 hectares, which is nearly 22 times larger than Central Park in New York.

Barcelona boasts 9 UNESCO World Heritage Sites, 7 of which are works by Antoni Gaudí, including the Sagrada Familia, Park Güell, and Casa Batlló, making it one of the cities with the most UNESCO-listed sites by a single architect.

Witnessing "Castells" (human towers) is a deeply rooted Catalan tradition, particularly during local festivals, where teams build intricate, multi-story human structures, often topped by a small child, symbolizing strength, balance, and courage.

While famous for Gaudí's Sagrada Familia, a lesser-known architectural marvel is the Palau de la Música Catalana, a stunning Modernista concert hall designed by Lluís Domènech i Montaner, which is a UNESCO World Heritage Site and the only concert hall in Europe illuminated by natural light during the day.

Barcelona is considered the cradle of Catalan Modernism, an architectural and artistic movement from the late 19th and early 20th centuries, which fused Art Nouveau with traditional Catalan elements, giving rise to iconic works by Gaudí, Domènech i Montaner, and Puig i Cadafalch.

Barcelona's metro system has a "ghost station" called "Correos" (Post Office) near Jaume I station. It was built but never opened to the public, though you can still glimpse its platforms if you know where to look between stops on Line 4.