With 2 million pilgrims and 200 world leaders descending on Rome in advance of Friday's papal funeral, the city is grappling with a logistics and security challenge that officials here have rarely seen before.
The previous two papal funerals, both of them in 1978, attracted a mere 750,000 and 500,000 mourners, respectively, and just a few heads of state.
But Friday's farewell to John Paul II is expected to draw several times those numbers, including President Bush, who will be the first American president to attend a papal memorial service.
That has sent Italian officials into an around-the-clock scramble to plan for both mundane and special needs, from security to thwart any terrorist attack to providing food, shelter and medical care to a number of visitors that may almost equal the city's 2.5 million population.
"For us, it will be an extraordinary challenge," Rome Mayor Walter Veltroni said.
Rome has hosted major world events before. In 2000, the city hosted several million visitors for the celebration of Christianity's 2,000th anniversary. But city officials had years to plan for that.
That celebration also took place before the Sept. 11, 2001, terrorist attacks heightened security concerns across the globe.
Michele Calderone, a spokesman for Italy's Interior Ministry, declined to discuss what security precautions would be taken to ensure the safety of the tens of thousands expected to jam into St. Peter's Square to be near the papal funeral service.
"There is a way of handling that, but we don't discuss those details," he said.
Metal detectors have been deployed in the past to screen all visitors who pass through the columns into St. Peter's Square, but they haven't been used in recent days. The crowds on the streets leading into the square have been huge as well.
Authorities are believed to be planning to use explosive-sniffing dogs, extensive video surveillance and snipers posted on rooftops around the Vatican. Reports said more than 6,000 extra police already have been deployed.
Others discount that the pope's funeral is a likely target for a terrorist attack. London-based terrorism expert Loretta Napoleoni, a Rome native, said militants probably haven't had enough time to plan an attack on St. Peter's, given how quickly the pope's health declined. It took the organizers of the 2003 Madrid train bombings a year to gather the necessary explosives, she noted.
More challenging may be the logistics of dealing with the deluge of people expected to arrive in Rome in the next few days.
To accommodate the pilgrims, a massive campsite is being set up on the outskirts of the city. Rome's Il Messaggero newspaper reported officials also are considering using sports venues, including the 80,000-seat Olympic Stadium, to house visitors.