Every four years, hundreds of American athletes trot into the Opening Ceremony of the Summer Olympics, but only one receives the honor of flag bearing.

The captains of each sport vote to decide on the position, and this year's honor belongs to fencer Mariel Zagunis. In the past, there have been household names such as Rafer Johnson and Dawn Staley. Others come with incredible stories like Lopez Lomong, a Sudanese refugee, or Cliff Meidl, who nearly died in a construction accident as a 20-year-old.

This tradition dates back to the opening ceremey of the 1908 London Olympics. Ralph Rose, the United States flag bearer, approached the royal box where Edward VII waited. The other nations had dipped their flags to the royal box, but Rose did not. He had been advised by teammates, especially the Irish-American ones, not to dip the flag. Field athlete Martin Sheridan is believed to have said, "This flag dips to no earthly king."

During the next 28 years, the U.S. only dipped the flag at the Summer Olympics in 1912 (Stockholm) and 1924 (Paris) and the 1932 Winter Olympics, which were played in Lake Placid, N.Y. with New York governor Franklin Roosevelt greeting the Parade of Nations.

At the 1936 Berlin Olympics, when the U.S. delegation approached Adolf Hitler, the flag was not dipped. The action at the 1936 Games inspired Americans to make the refusal to flag dip a tradition. In 1942, the United States Congress introduced Public Law 829 in the United States Flag Code Public Law. It reads: "That no disrespect should be given to the flag of the United States of America, the flag should not be dipped to any person or thing." In other words, the refusal to flag dip is not a tradition. It is a written law.

Here are all the Opening Ceremony flag bearers for the U.S., dating back to the origin:

Follow us on Facebook and Twitter to read them first!

The Rock Thanks The Iron Sheik