PHILADELPHIA -- For most of the 20th century, this city had an informal rule that no downtown building could stand taller than Billy Penn's hat.
"There was nothing written into law. It was a gentlemen's agreement," said developer Garrett Miller, who plans to break the old rule in a big way with a new office building that would tower more than 1,500 feet above the street and, at least for a while, be the third highest structure in North America.
City Hall here is topped by a statue of Pennsylvania founder William Penn, and his hat is 548 feet above the street. From its opening in 1901 until 1987, City Hall was the tallest building in the city. The unwritten rule was finally broken that year when One Liberty Place, an office building, opened at a height of 945 feet.
That building lost its No. 1 ranking in Philly last year when the sleek, glassy Comcast Center opened at 975 feet high. By comparison, the 64-story U.S. Steel Tower in Pittsburgh, which opened in 1970, is 841 feet high.
Now Mr. Miller and his company, Hill International Real Estate Partners, expect to start construction later this year on a huge new office tower that will climb far past the Comcast building and make Billy Penn even harder to see on the city's skyline.
The proposed American Commerce Center, which has almost all the municipal approvals it needs but is still looking for an anchor tenant, would soar to 1,510 feet above the street. City officials removed the previous 125-foot limit for the property, but final approval from City Council is still needed.
The $1.1 billion project, with 2.2 million square feet of space, would combine more than 60 floors of offices with about 26 stories of hotel rooms, plus several floors for utilities and some retail space, such as a department store, a theater and possibly a supermarket on the lower floors.
"I think Philadelphia is starting to recognize that for it to grow and mature as a city, it needs to go vertical," Mr. Miller said in a recent interview. "The blending of old and new creates an exciting and dynamic contrast."
He said his building would "create an opportunity to attract companies, attention, tourism and pride in Philadelphia."
The site of the proposed tower is now a surface parking lot bounded by 18th and 19th streets, and Arch and Cuthbert streets. The site is a mere half block from the Comcast Center, which opened last summer. In between Comcast and the proposed Commerce Center is the tiny Arch Street Presbyterian Church, a two-story structure topped by a green dome. It clearly would be dwarfed for good by its two tall neighbors.
Mr. Miller is hoping to start construction this year and complete the tower, perhaps, by 2012. He wouldn't discuss possible tenants, but Philadelphia Business Journal has mentioned that GlaxoSmithKline is a possibility for an anchor tenant.
At 1,510 feet high, the American Commerce Center would, at least for a few years, be the third tallest building in North America, after the CN (Canadian National) Tower in Toronto, which opened in 1976 at 1,815 feet high, and the Sears Tower in Chicago. The Sears Tower opened in 1973 at 1,450 feet high, but two TV antennas were added in the 1980s, one reaching 1,730 feet and the other 1,707 feet.
In a few years, however, the American Commerce Center could sink to the fifth highest building if the Chicago Spire office building hits 2,000 feet high, and the Freedom Tower, a new building in New York City on the site of the former World Trade Center, comes in at 1,776 feet high.
The World Trade Center in New York City had been in third place in North America until it was demolished in terrorist attacks on Sept. 11, 2001. Its north tower was 1,368 feet high and the south tower was 1,362 feet high.
Determining which skyscraper is the tallest in North America -- or in the entire world -- can be tricky, because contractors are always trying to top one another.
Currently the Empire State Building in New York City, at 1,250 feet high, is the third-highest building in North America. But magnate Donald Trump is building a Trump hotel and tower in Chicago, which next year will open and take over third place, at 1,362 feet high.
But several other buildings around the world, in places such as Shanghai, Hong Kong, Taipei, Kuala Lumpur and Dubai, are taller than North America's highest.
The tallest building in the world is the Burj Dubai, or Dubai Tower. It stood at 2,320 feet tall in September and was to have been completed in about a year, at 2,600 feet. But developers last week announced that construction has been halted for a while due to the worldwide financial crisis.
Advances in architectural and construction technologies allow for ever-higher buildings, Mr. Miller said.
"It's part of human evolution to push the boundaries" of construction, he said. Egos of architects and developers also may have something to do with it.
Mr. Miller believes tall buildings are the way to go in large cities, because land isn't available to build out horizontally, so there's nowhere to go but up. He doesn't think much of scads of surface parking, either. He likes the fact that Center City is well-served by mass transit.
"Density is a good thing," he said, referring to putting a lot of people on a small footprint of land in a city. "Cities should build tall buildings. They are symbols of human progress, and a source of pride for cities."
Controversy arose over a $42 million state development grant that Gov. Ed Rendell, a former mayor of Philadelphia, got four years ago to help finance the Comcast Center skyscraper. Some Republican legislators from rural areas weren't keen on that grant.
Mr. Miller said it's likely some state financial help would be needed for his project also. He contended there's nothing wrong with that.
"Philadelphia and Pittsburgh are the economic engines of Pennsylvania," he said. "The Legislature should be focused on helping cities thrive and grow. That's a good thing."
Harrisburg Bureau Chief Tom Barnes can be reached at email@example.com or 1-717-787-4254.