A small army of security forces, shuttered Metro stops, re-routed buses - Washington will leave nothing to chance next week to protect leaders at President Barack Obama's nuclear security summit.
The 47-nation summit, the most vast international gathering the US capital has seen in decades, will draw on security know-how and manpower on a staggering scale and place parts of the capital on lockdown, officials said.
"The level of security needed... is immense," said Washington Mayor Adrian Fenty, noting that the city is no stranger to "big events" like presidential funerals or visits by the Dalai Lama, the Pope, or Britain's Queen Elizabeth.
But this gathering is "without any question one of the biggest, most prestigious important meetings that has ever taken place not just in this city but anywhere in the world," he said.
Motorcades zooming to and from the White House or the State Department are nothing new to Washington, blockaded streets come and go with events like World Bank or IMF meetings, but even jaded citizens may be in for some headaches.
"Be patient with us. This is Washington DC, we do a lot of big events here. It's a world class city and I think we do them very well," said the city's police chief, Cathy Lanier.
Each world leader is expected to bring their security detail, but the Obama's US Secret Service bodyguards are overseeing the overall effort to keep visiting dignitaries safe starting Sunday.
"There will be different layers of security that will include a variety of different things visible and not visible," said Lanier, who declined to give precise numbers of agents deployed "for security reasons."