The 6888th Central Postal Directory Battalion was the only one comprised of Black women to be sent overseas during World War II.

On Tuesday, the 6888th Central Postal Directory Battalion — the only mostly Black, all-women unit to serve overseas during World War II — was awarded the Congressional Gold Medal, Congress’ highest civilian honor, at the U.S. Capitol, according to ABC News.

Black female unit, recognized for its vital wartime contributions, sorted a 17 million mail backlog in three months and was recognized for its vital wartime contributions.