First Botticelli, now Boccioni: eco activists glue themselves to Futurist sculpture in Milan
More protest actions will follow, says Ultima Generazione group
'The complicated history of Boccioni sculpture is no barrier to record price at Christie's in New York'
Futurist bronze sculpture cast from another bronze in the 1970s sells for $16.2m—four times its estimate
Futurist masterpiece by Umberto Boccioni could sell at Christie's for up to $4.5m
A different version of the sculpture Unique Forms of Continuity in Space sold at the auction house in 1975 for $41,000