The block of Market Street where two buildings collapsed today is not just one of the most blighted stretches remaining in Center City; it is a block where blight was ignored for decades by successive city administrations.

The collection of small, decrepit commerical buildings, which includes Hoagie City and the Salvation Army Thrift Store, was once part a larger empire of blight assembled by Philadelphia's most notorious slumlord, Sam Rappaport. Even as the rest of Center City took on a polished gloss, the deteriorated Market Street buildings were among the first things people saw as they entered the city from 30th Street Station.

After Rappaport's death in 1994, most of the buildings on the 2100 and 2200 blocks of Market Street fell under the ownership of Richard Basciano, dubbed the "undisputed king of Times Square porn" in the mid-'80s by the New York Times. Basciano was the landlord for two porn operations on Market Street, the Forum Theater and Les Gals, anachronistic establishments that offered XXX movies and peep shows long after that sort of porn had migrated to the internet.

In an attempt to salvage the business, Basciano's operator, Anthony Trombetta, applied to the city zoning board in 2010 for permission to enlarge the Forum to accommodate more booths where customers could interact with performers. Despite evidence of prostitution and other violations, the city approved the application. It was only overturned after the Center City Residents Associations wages a legal battle.

Even after that debacle, the city did little to push Basciano into cleaning up the battered stretch.

Then late last year, the 87-year-old slumlord announced he had a change of heart and would raze his crumbling buildings in an effort to market the blocks for development. After the Forum was demolished, work moved to Les Gals and a rowhouse-size building that housed Hoagie City, which collapsed on the Salvation Army.

In typical fashion, the demolition got off to a bad start. In January, his workers began ripping apart the Forum theater before they had secured a demolition permit.

Joseph Sulvetta, an architect who works nearby, said he always wondered about the quality of the demolition work. "It wasn't the highest skilled demolition crew," he said. "They took off the Forum marquee without shutting down the street. It was a couple of guys with sledge hammers."

On Sunday, as he walked past the demolition site, Sulvetta said he again remarked at the poor quality of the work. A backhoe had just taken off a piece of the Hoagie City building and a two-story-high party wall loomed over the Salvation Army building next door.

"I said to myself, 'This doesn't look safe'," he said. "But I knew they had gotten a permit and I assumed L&I was on top of it."