Cotton House Hotel, Barcelona. Net-A-Porter.
This sleek 19th-century pile (the former HQ of the Cotton Textile Foundation) has been luxuriously renovated by interior designer Lázaro Rosa-Violán, who preserved original details like the gleaming marble staircase and the parquet floors. Expect 300-thread-count Egyptian sheets and lavish Ortigia bathroom products in your suite. 
Insider tip: The lush Batuar terrace bar offers non-stop service from 7am until midnight from its upscale Catalan menu. From €180;