Casa Batlló

In one of the most extreme architectural makeovers ever seen, Antoni Gaudí and his long-time collaborator Josep Maria Jujol took an ordinary apartment block and remodelled it inside and out for textile tycoon Josep Batlló between 1902 and 1906. The result was one of the most impressive and admired of all Gaudí's creations. Opinions differ on what the building's remarkable façade represents, particularly its polychrome shimmering walls, its sinister skeletal balconies and its humpbacked scaly roof. Some say it's the spirit of carnival, others a Costa Brava cove. However, the most popular theory, which takes into account the architect's deeply patriotic feelings, is that it depicts Sant Jordi and the dragon – the idea being that the cross on top is the knight's lance, the roof is the back of the beast, and the balconies below are the skulls and bones of its hapless victims.

The chance to explore the interior (at a cost) offers the best opportunity of understanding how Gaudí, sometimes considered the lord of the bombastic and overblown, was really the master of tiny details – from the ingenious ventilation in the doors to the amazing natural light reflecting off the inner courtyard's azure walls, and the way the brass window handles are curved so as to fit the shape of a hand. An apartment is open to the public, and access has been granted to the attic and roof terrace: the whitewashed arched rooms of the top floor, originally used for laundering and hanging clothes, are among the master's most atmospheric spaces.