Art market faces uncertain 2017 after falling values and high-profile disputes

A drop in volume, court battles and authenticity issues dogged 2016 and no one is sure if the new presidency will be good or bad for business

This $500 shirt changes color when exposed to air pollution – but who does it help?

A NYC-based designer says he wants to make people pay more attention to the environment. But at these prices, is this more art than activism?

Art Basel Miami: how the art fair landscape reflects Trump’s America

The current US climate has led to a racially charged and overtly political range of artworks on display at this year’s show

Laura Cumming: best art of 2016

Portraits woke up, the tiny Goldfinch flew in, the Switch House switched on, and junk art triumphed

• Observer critics’ reviews of the year in full

Google’s satellite timelapses show the inconvenient truth about our planet

Google’s new Timelapse project allows you to see how anywhere in the world has changed in the last 32 years; from evaporating lakes to exploding cities, it’s a document of recklessness

Robert Rauschenberg review – six sensational decades of work finally reveal the man in full

Tate Modern, London
Driven by an insatiable curiosity, the groundbreaking artist took the triumphs and wreckage of American life and turned them into art – and this brilliant show captures his extraordinary range