system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
What caused the millenium tower to sink in san francisco?


assistant
The critics blame the city for allowing Millennium partners to anchor the building into packed sand rather than bedrock. The problem with Millennium tower arose because the 60 to 90-foot-long friction piles supporting it were driven into sandy soil rather than the bedrock, 200 feet down.