11:45 AM PT -- The daredevil has been ID'ed as Maison Des Champs -- a rock climber who calls himself the "Pro-Life Spider-Man."
On his personal website, he says he's transitioned to climbing skyscrapers in an effort to end abortion.
Instagram / @prolifespiderman
The climber posted videos to his social media page mid-ascent on Tuesday, and said the climb was "not that hard."
No word on if he's been officially arrested -- we've reached out to cops for comment, but have not received a response yet.
11:27 AM PT -- S.F. Fire Department officials say the climber is now off the structure and currently with police.
Unreal scene in San Francisco on Tuesday morning ... a daredevil is climbing up the city's tallest skyscraper -- with no ropes or safety nets.
The urban climber began his ascent on the Salesforce Tower in the middle of downtown S.F. shortly after sunrise -- and as of this posting, he's nearly made it to the top of the 60-floor, 1,070-foot tall building.