This is not a good example for your comment, as the building that collapsed was in the process of being demolished in order to put up a new building and everything was in order with the licenses and permits to do that.  (So working on building a new city, in this instance did not have a good result at all.)

The  deaths and injuries happened because the uncontrolled collapse of the partially demolished building fell on the thrift store next door and it is not known yet why it happened (Jon Hurdle for the NYTimes):

The cause of the collapse, which occurred on Market Street near 22nd Street, was not immediately known. Several government agencies, including the federal Occupational Safety and Health Administration, will investigate.

The building’s permits were in order, and no violations were listed against it, said Carlton Williams, Philadelphia’s commissioner of licenses and inspections. He identified the owner as STB Investments of New York, and said city authorities had contacted the company.

A demolition permit for the building was issued in February, Mr. Williams said.