The French daredevil Alain Robert said his climb of the 52 story new york times building was to raise awareness of global warming, in relation to the UN World Environment day.
Using the lattice work on the facade, Mr Robert climbed without equipment besides chalk for his hands and climbing shoes.
He was greeted at the top by police who arrested him.
His climbs are often illegal, usually without permission and always without rope for protection.
Last year he was jailed for five days in
An interesting fact was, after his climb, a unknown copycat climber also scaled the same building, watched by rush hour crowds who cheered as he reached the top.
This mystery climber was also greeted by police, who took him away immediately.