A nearly forgotten underground wall could prove a serious obstacle to reversing the tilt of the Millennium Tower, a major goal of the $100 million fix for the troubled San Francisco high rise, experts tell NBC Bay Area’s Investigative Unit. Jaxon Van Derbeken reports. Stay connected: Follow us on Twitter: http://www.twitter.com/nbcbayarea Like us on Facebook: http://www.facebook.com/nbcbayarea Follow us on Instagram: http://www.instagram.com/nbcbayarea Follow us on TikTok: https://www.tiktok.com/@nbcbayarea Catch up on all the day's news: http://www.nbcbayarea.com Download our mobile app: On iOS: http://nbcbay.com/R1BhqYM On Android: http://nbcbay.com/rUcA97h Watch us on OTT: Add our channel on Roku: https://bit.ly/3ySK60j Download our app on Amazon Fire TV: https://amzn.to/3FmmiE Show more