A French daredevil scaled a 73-story Hong Kong skyscraper barehanded Tuesday, his latest attempt to draw attention to global warming by climbing up the world's tallest buildings.

Alain Robert, dubbed the French spider-man, has scaled dozens of tall structures without ropes or harnesses, including the Eiffel Tower in Paris, the Empire State Building in New York and Malaysia's Petronas Towers in Kuala Lumpur.

It took Robert about 40 minutes Tuesday to scramble up the downtown Cheung Kong Center — the flagship building of Hong Kong's richest man, Li Ka-shing. Upon reaching the top of the 885.83-foot building, Robert waved to a crowd of spectators on the ground below.

The 46-year-old said police officers questioned him after the ascent, but released him without any charges.

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Robert said he hoped his climbs could help bring attention to the world's environmental problems.

"The global warming is something that is going to affect the next generation," Robert told reporters on the ground level. "The future is really compromised if we are not doing anything."

Police spokesman Lawrence Li said they were aware of a man outside the building and that he was safe. Li said officers did not press any charge against the man.

It's the fourth time Robert has mounted a skyscraper in Hong Kong. He scrambled up the city's 45-story Four Seasons hotel last year.