When the Group of 20 summit takes place in Pittsburgh, the mayor hopes not only to show off the city's economic achievements, but also to demonstrate it can host an orderly meeting of the world's leaders – while allowing protesters to march.
However, protesters are being kept a long distance from the delegates, and the city has acted quickly to limit demonstrators' mobility.
"We want to make sure everyone's First Amendment right is honored and they have the ability to protest and talk about the issues," says Mayor Luke Ravenstahl. "We welcome that. But those who are here to destroy property, cause harm, threaten individuals – that's where the line is crossed."
The Seattle police chief at the time, Norm Stamper, wrote a book in 2005, and one of his admissions was that he was unprepared for the WTO protesters.
Mayor Ravenstahl says he's read parts of the book. "That's been very interesting reading for me to understand the dynamics of what we may face with the G-20," he says.
One lesson, he says, is that Seattle did not have enough police. The city had about 900 police officers – about the same as Pittsburgh's police force.
That's why Pittsburgh will import police from around the region, Ravenstahl says. By the time G-20 leaders arrive, he says, as many as 4,000 law enforcement officials could be on the streets.
By Wednesday night, the city expects to separate the downtown area into a red zone and a green zone. The red zone will be locked down with metal fences, and only credentialed individuals will be allowed in. The green zone will be heavily policed.
Some businesses have already boarded up their windows in anticipation of possible violence. The city has encouraged most downtown businesses to close for the G-20.
The result: Downtown Pittsburgh will be quite deserted once world leaders arrive.