According to the on-screen information during the opening ceremonies/parade of nations, there are 647 US athletes in Beijing.
During the Olympic Games opening ceremonies, an artistic program is designed by the hosting country to display the history and culture of their home. In addition, the Parade of Nations takes place, in which the athletes march into the stadium to represent their country.
The opening ceremonies signify the official start to each Olympic Games. An artistic program is designed by each hosting country to perform as an exhibition. In addition, the Parade of Nations takes place, in which the athletes march into the stadium to represent their country.
The host country shares its culture. then all the atheletes parade around during the ceremonys. then the torch is lit
The athletes from China will be the last to enter during the opening ceremonies. Olympic protocol dictates that the host country's athletes enter last at the opening ceremony.
Greece enters the stadium during opening ceremonies first in respect to the Olympics beginning there and the host country enters last.
I'm assuming this is in the 2010 Olympic games, in which case Clara Hughes carried the Canadian Flag during the opening ceremonies.
The host country's team marches in last during the Opening Ceremony's Athletes' Parade.
Greece, in honor of where the Olympics began.
The opening ceremony starts the Games and the closing ceremony ends the Games. The medal presentations could also be considered a ceremony albeit to a much small extent as the opening and closing ceremonies.