Alex Honnold isn’t the first person to climb Taipei 101, but he is the first known to have done it without ropes or safety nets.

Urban climber Alain Robert, also known as the “French Spiderman,” climbed the 101-story Taiwanese skyscraper as part of the building’s opening in 2004. He gave commentary on Honnold’s climb today in CNN’s live coverage.

With a safety belt and rope, Robert took four hours to complete the ascent on Christmas Day amid rainy weather. The building also wasn’t finished at the time, with some metal beams still bearing slippery vinyl covers, complicating his attempt.

The two climbers compared notes on a recent episode of Honnold’s podcast “Climbing Gold,” in which Robert advised Honnold to take breaks and fuel up if needed after climbing each of the eight segments on the tower’s exterior.

The rock climber turned his attention to urban feats in the mid-1990s. The 63-year-old usually completes his summits without the help of any safety equipment, relying only on his bare hands and a small bag of chalk for better grip.

Robert has climbed several famous landmarks, including New York’s Empire State Building, the Petronas Towers in Kuala Lumpur, Dubai’s Burj Khalifa, and the Eiffel Tower in Paris — some of which he did free solo.

While some of Robert’s escapades are done legally — after being invited by countries or enterprises to “christen” the unveiling of a new building — he has been arrested over 120 times for similar stunts.

“Life has to be dangerous,” Robert told CNN in a 2010 interview. “There is a percentage of people who want to be a little bit outside their comfort zone and I am one of them, someone who lives on the edge.”