Rowan Moore: the best architecture of 2015

From dumb towers to cool interventions, 2015 saw the gap widen between the big and brainless and the small and thoughtful

• Observer critics’ reviews of the year in full

Laura Cumming: the best art of 2015

It was a wonderful year, as Goya’s extraordinary portraits got together, Ai Weiwei broke free and Eric Ravilious took us to the skies

• Observer critics’ reviews of the year in full