This Gaudí masterpiece was recently rescued from obscurity, and opened to the public in 2013. Built between 1900 and 1909, this private residence (still owned by the original Guilera family) has a castle-like appearance with crenellated walls of stone and brick, narrow stained-glass windows, elaborate ironwork and a soaring turret mounted by a Gaudian cross. It's a fascinating work that combines both Gothic and Modernista elements.
Guided tours in English (€16 per person) happen daily at 11am and include the interior of the building; otherwise visits are limited to the grounds – its gardens and stables, but do include an audioguide that gives historical background. The other downside: it's a long walk to a train station, though many buses pass near (including bus 22 and bus 58 from Plaça de Catalunya).