The works of Antoni Gaudí are among the most visited sights in Barcelona and it is hardly possible to resist the fascination of these buildings, even if you are not a fan of modern architecture. On our trip to Barcelona in May 2014 we managed to visit all seven inscribed sites.

The entire façade of the Casa Milà is currently under scaffolding (according to the information at the ticket counter until early 2015), but this does not affect the visit of the interior. The highlight is the rooftop, a garden of spectacularly designed chimneys, ventilation shafts and staircase exits grouped around the two courtyards. In the attic is an interesting exhibition which explains Gaudí's architectural principles by means of models of his most important works. Finally, you can visit an apartment with furniture from the early 20th century, but it is not very interesting and has no connection with Gaudí.

Casa Batlló probably provides the most comprehensive impression of Gaudí's ideas. He redesigned an existing building in the style of Modernisme, including the interior, such as lighting, windows, doors, stair railings etc. I was most impressed by the central light well, which is completely covered with blue ceramic tiles. The colour of the tiles is darker at the top floor, and if you look from the ground floor upwards, you have the impression of a uniform blue colour. With an audioguide you can visit the former apartment of the Batlló family, the central staircase, the attic (also a highlight for architecture fans), and the roof terrace. The colourful façade is a symbolic illustration of the legend of Saint George and the dragon. And the building is beautifully illuminated at night.

The Palau Güell was reopened for the public in 2011 after years of restoration. It was one of the first works of Gaudí, but his style and his attention to detail are already apparent. The visit was a real surprise. Most striking is the elaborate design of the ceilings, stairs and railings. There is lavish decoration, lots of precious wood with inlays. The living rooms are grouped around a central hall (photo) with a parabolic dome. You can visit the entire building, from the vestibule in the ground floor up to the roof terrace (again with the typical chimneys and ventilation shafts).

The Park Güell north of the city centre is another highlight. You have to pay an entrance fee for the so-called monumental zone which comprises the well-known parts of the park: the entrance pavilions, the columned hall (Sala Hipóstila), and the terrace with benches, which are decorated with mosaics from ceramic shards. From the terrace you can enjoy spectacular views over Barcelona. But it is also worthwhile to explore the outer areas of the park with several bridges and colonnades made from unhewn stone. These parts are freely accessible and also within the core zone of the WHS.

The Casa Vicens is not open to the public (a museum is planned for 2016), but the façade is worth seeing. It was obviously inspired by the Mudéjar style and is very different from other Gaudí buildings. A detour to Casa Vicens can easily be combined with a visit of Park Guell, it is just a walk of 20 minutes from the main entrance of the park.

The Sagrada Familia is a must-see for most Barcelona tourists, absolutely understandable, the interior of this unique basilica is overwhelming. But only the Nativity façade and the Crypt are parts of the WHS. Both can be visited free of charge. The sculptures of the façade can be seen from outside the barrier (best with a pair of binoculars or a telephoto lens) and the Crypt is freely accessible. But the opening times differ from those of the Basilica, on our visit from 9 to 10 am and 6 to 9 pm.

Finally, the Crypt of the Colonia Güell: at first glance it is less impressive than other Gaudi buildings, but the inscription is absolutely justified. In this unfinished building, Gaudí has realized for the first time several typical structural elements and innovative techniques. It is worthwhile to explore the entire Colònia Güell, the visitor centre offers an audioguide. It was a nice half day trip (20 min by FGC from Plaza España) and a pleasant escape from the crowded city centre.

It is quite costly to visit all six sites, we paid about 80 Euro per person. Thus, visitors who are not enthusiasts of modern architecture will probably visit one or two sites and view the others from the outside only. Not easy to give a recommendation, but I would suggest to visit at least Casa Batlló and the Park Güell. Despite the steep entrance fees there are long queues at most of the sites. Thus it is best to visit either early in the morning or in the evening. Or to buy tickets online (possible for all five sites in Barcelona), but you have to book a fixed time slot (except for Casa Batlló). We bought tickets online for the Sagrada Familia, Casa Mila, and Casa Batlló.

All in all, one of my favourites WHS among those I've visited so far.