Barcelona's Sagrada Familia

Antoni Gaudí took the architectural style known as Art Nouveau a step further, even, some have argued, into absurdity. The fanciful and outrageous buildings he created in Barcelona have become landmarks, the most emblematic tourist attractions of this Catalan city.

Foremost is the Basílica de la Sagrada Família, officially the Temple Expiatori de la Sagrada Família or the Holy Family Church of the Atonement. One of Europe's most unconventional churches, it is also unfinished, so as you look down from its tower, you can see the work in progress below.

You may search in vain for absolute straight lines in Gaudí's Casa Milà, his last and most famous secular work; it resembles a piece of sculpture more than a functional building. Be sure to ascend to its roof – the chimneys are said to have inspired the image of Darth Vader from Star Wars.

New in 2022, the fantastic Casa Batlló, an iconic Gaudí building with mask-shaped balconies and an undulating façade, presents Magic Nights outdoor concerts on the building's rooftop terrace.

Parc Güell overlooks the city from a hillside, the views and gardens framed by fantastical creatures – salamanders, fish, an octopus – and designs in bright ceramic-chard mosaics. A fanciful towered house near the entrance is largely covered with colorful ceramic pieces.

Gaudí's monuments appeal even to children and to adults who don't care a thing about architecture, for one simple reason: they are just plain fun to look at.