Yellow Ribbon
During the Iran hostage crisis, the yellow ribbon was used as a symbol of support for the hostages held at the United States embassy in Tehran.[5][8] In November 1979, a committee headed by Suzan E. Garrett of the Jaycees ladies service organization in Leitchfield, Kentucky organized a campaign to "Tie A Yellow Ribbon" around public trees as well as encouraging people to wear tied ribbons on lapels in support of the U.S. hostages being held in Iran. She was interviewed on ABC-TV by Ted Koppel on the newly created Nightline late-night news program and later by Peter Jennings for ABC's World News Tonight.

This symbolism continued and gained further recognition in December 1979, when Penelope Laingen, wife of Bruce Laingen who was the most senior foreign service officer being held hostage, tied a yellow ribbon around a tree on the lawn of her Maryland home. The ribbon primarily symbolized the resolve of the American people to win the hostages' safe release.[5] Yellow ribbons featured prominently in the celebrations of their return home in January 1981.

The yellow ribbon saw renewed popularity in the United States during the Gulf War in the early 1990s. It appeared along with the slogan "support our troops", in the form of yellow ribbons tied to trees, and countless other contexts.[5] It often had the implied meaning of "bring our troops home"[8] from the Desert Shield and Desert Storm troop deployments. It appeared again during the 2003 invasion of Iraq with similar meanings,[5] most prominently in the form of a yellow ribbon printed on magnetized material and displayed on the outside of automobiles.
https://en.m.wikipedia.org/wiki/Yellow_ribbon