Having visited the Sagrada Familia and Park Guell, we wanted to visit one of Gaudí's houses too, the only problem was which one to choose. We eventually went for La Perdrera (aka Casa Milà), as we had passed this intriguing building several times and really wanted to see the unusual roof which we thought would offer great views of the city.

The facade of the building is said to have no straight lines in it whatsoever, and its undulating, organic shape, is further enhanced by the wrought iron plant-like forms which adorn the balconies. The building owes its nickname la Perdrera to the quarry-like aspect of its frontage.

On entering, the courtyard is also impressive, its shape drawing the eye up towards the little bit of sky at the top. The visit is in several parts, and equipped with our audio commentary, we first visited the 2 carefully restored apartments which took us back in time to when the building was new. The first is a bit like a museum, showing all the technological novelties of the time, telephone, cinema and so on. The second one was a reconstruction of an apartment in the modernista style, mixing designer and everyday objects. Remember to look at the interior patio from the apartment windows.

Having seen the apartments, we were keen to get on the roof, not realising that there was a major part of the visit to experience before that, the 'Espai Gaudí'. The roof space, which was once used to dry laundry, is now an exhibition of Gaudí's life and work. I was most impressed with the space itself, with all its brick arches, and surprised at how beautiful it was, considering that it was not on show, but only seen by a few. This part of the visit made me glad we chose to visit this building, as there were displays on many of his other works which gave a really good overview of his style and techniques. There were pictures of buildings that are not normally visited which was interesting. I was fascinated by an upside down model of a building made of string with weights attached which demonstrated one of Gaudí's techniques for designing arches. If you looked in the mirror that was placed below the model, you could see what the building would look like. The coordinate were entered in a computer and it was found that modern techniques could not have designed it better.

The roof terrace was great fun. The surface was not flat, but curvy, and functional objects like chimneys and ventilation shafts are given interesting shapes (owls, helmeted warriors and so on) and textures (broken pottery, marble, even broken champagne bottles).

The gift shop can be entered from the street or from the Casa Milà, but you cannot return to the visit from there.

At €6 plus €3 for the audio-guide, this was excellent value for money. Discounts are available for holders of a current 'bus turistic' ticket.

Casa Mila was another fabulous must-see sight, not to mention that it has an almost unrealistic exterior structure, and the roof top garden was also very magical. It was said that the apartment block was built without any straight line or right-angle corners, so everything looked really smooth, flowing, and alive (you know what I mean?). The admission cost is significantly lower than Casa Batllo, and there's a fabulous museum about Gaudi's architecture in there, so it's definitely worth a visit! Aside from the cool rooftop (I somehow felt like I was on a beach when I was up there) and the fantastic museum (with an audio guide included), the apartments and the lobby of the entrances were also very amazing!

"Come on," my husband said, "they're still open," as he ushered me toward La Pedrera, or Casa Mila, one of Gaudi's finest architectural achievements. After a long day walking throughout the parks and streets of Barcelona, I was exhausted, but as soon as I saw the building, I was immediately hooked.

"Wow," I murmured as we approached the sinuous facade quite unlike anything else on the boulevard. La Pedrera, or the Stone Quarry, occupies the corner of the block. The first thing I noticed was the oddly shaped chimneys at the top of the building. Evidently these chimneys were so unnerving to Barcelona citizens when they were constructed they were nicknamed "espantabruxes" or witch scarers. The building was not widely accepted by Barcelonians when it first opened in 1910. In fact, the nickname, La Pedrera, was intended to convey the belief the building was simply a pile of rocks.

Another incredible aspect to the front façade were the fantastic balconies, shaped a bit like caves with black wrought-iron railings so intricate, they look like seaweed. We paid 7 Euros to enter the building, which is largely an apartment building but we were able to visit an example of the apartments called the Pis de la Pedrera. This apartment was filled with 20th century furniture. One feature of this building is the paucity of right angles in the rooms and when combined with the vaulted ceilings, this tends to produce a very spacious feel.

We next went up to the Espai Gaudi (Gaudi’s space) in the attic where we admired the incredible arches and curves lining the top of the building and serving as an insulating cushion for the bottom floors. This area has some terrific displays and models describing Gaudi’s work from across Spain, as well as an upside down model of the Sagrada Familia building. (More on that in the Sagrada Familia entry.)

From the attic we went on up to the roof, and as night had descended on the city, the roof had come alive. The spooky chimneys were illuminated with strong beams of lights, and we wandered around the roof for about 45 minutes, enjoying the atmosphere. We had the space largely to ourselves as it was late in the day. The place was more awesome than spooky, more spiritual than creepy, and we were both struck by the quiet beauty of the lines and columns.

Visiting La Pedrera was easily the best activity of our time in Barcelona, and although we did not plan to be there at nighttime, it turned out to be the perfect time to go.

This huge palace is another masterpiece by Gaudì. It was built between 1906 and 1912. Its name, "La Pedrera", means the stone quarry. Casa Milà looks like a grey petrified wave. Its rooftop has many chimneys that seem like giant warriors.

This was something well worth the wait after the long queues. The building is divided into different sections. The fourth floor has been left as an example of an early-20th-century 'modernista' flat, and above this there is a section dedicated to drawings, models and film footage of Gaudi's work. I personally found the rooftop area the most exciting - from here you can look around the abstract sculptures whilst on a clear bright day looking for miles around the city, espying the 'Sagrada Familia' in the distance!