Palau Güell

Completed in 1890 for industrialist Eusebi Güell, Palau Güell shows Gaudí working within the constraints of a narrow city plot and a demanding client, using parabolic arches, wrought iron, and a soaring central hall lit from above to make the tight space feel monumental. It's UNESCO-listed and often described by visitors as an underrated stop that shows Gaudí's early career before his style became more famous, and more crowded, elsewhere in the city. The rooftop terrace, covered in twisting chimney sculptures finished in trencadís mosaic, previews the shapes he'd later develop at Park Güell and the Sagrada Família's towers. A booked timeslot is required, but the modest scale keeps the visit focused and unhurried, at around an hour.