When I first arrived in the city in 1988, it was Barcelona architecture that made me fall in love with it.
Barcelona struck at first like a kind of rundown Paris, just as impressive but somehow much comfier and more approachable.
That was more than 25 years ago, and since then Barcelona architects, such as Gaudí have achieved superstar status, and many of the most famous Barcelona buildings, are now clearly marked on the international tourist map.
For historical reasons, architecture in Barcelona has two amazing periods.
The Gothic Architecture in Barcelona was built between the twelfth and the fifteenth centuries.
Barcelona entered a lengthy period of decline and then came back with a bang towards the end of the 19th century and the irruption of Catalan Modernist architecture.
When I was looking for a single image to sum up what Barcelona architecture is for me, I decided on the building in the picture above - El Castell dels Tres Dragons, which was built by Lluís Domènech i Montaner in 1888 and is located in the Parc de la Ciutadella.
This building was built for the Barcelona Universal Exhibition and is generally considered the first example of Barcelona
Modernist architecture, and shows how Modernisme was influenced by the glorious period of Catalan history that Barcelona Gothic architecture was seen to represent.
Barcelona's Gothic Quarter - El Barri Gòtic - is possibly the best-preserved Gothic city centre in Europe, although what strikes you about Catalan Gothic buildings is that they are much squatter and more compact than Gothic buildings in other countries.
The Barri Gòtic is centred on Plaça Sant Jaume with its two government buildings, the Palau de la Generalitat and the Casa de la Ciutat and the nearby Barcelona Cathedral.
Other important Gothic churches in the city centre are Santa Maria del Mar and Santa Maria del Pi whilst Sant Pau del Camp and the Monestir de Pedralbes are further out.
The Barri Gòtic is a feast of Gothic architecture and you should also visit the urban palaces on Carrer Moncada, the Palau Reial Major and La Llotja to get a good idea of the style.
Obviously, the figure of Gaudí towers over the architectural style known in Barcelona as Modernism but perhaps best described as Catalan Art Nouveau.
You should also make a point of visiting the magnificent Palau Güell on Carrer Nou de la Rambla, and you can even have dinner at Casa Calvet, which is now a restaurant on Carrer Casp.
However, don't be misled into thinking that Barcelona Modernista Architecture starts and ends with Gaudí.
I've already mentioned Domènech i Montaner, who was a few years Gaudí's senior and the architect responsible for launching Catalan Modernism as an aesthetic movement through his work as Professor at the architecture school.
Moving on to more modern times, Modernisme was replaced by Noucentisme, which with its classical lines allures to Barcelona's Mediterranean identity by offering Neoclassicist image of Catalonia.
Good examples of Noucentisme can be seen on the walk up from Plaça d'Espanya to Montjuïc.
There are obviously many modern examples of Barcelona architecture, such as the Torre Agbar or Hotel W.
I wonder sometimes, though, whether these are beautiful buildings or just eyesores!