The Capitol building sits on a 59-acre park that includes hundreds of trees.
The newest, a sycamore , was planted just today, in memory of a black teenager whose murder, nearly 60 years ago, helped spark the civil rights movement.
"It was the end of my innocence as a child," said journalist and playwright Janet Langhart Cohen. The year 1955 changed her life.
"That August we got word from Money, Mississippi that a 14 year-old black boy, same age as I am, was brutally murdered for whistling at a white woman."
His name was Emmett Till.
On August 28th, 1955, the Chicago teen was taken by a group of white men from his great-uncle's home while visiting Money, Miss. His shot and battered body was found three days later in a nearby river. Two white men were acquitted. At Till's funeral, his mother Mamie proclaimed: Let the world see what they did to my boy.
Fifty thousand people filed by his open casket.
Asked what goes through her mind when she sees the image of Till's corpse, Cohen replied:
"It doesn't go through my mind, it goes through my heart. It breaks my heart to look at it because, I think of his mother."
Mamie Till spoke of her son before her death in 2003:
"He had a bullet through his head and I could see to the other side, and I thought, 'Did they really have to shoot him?'"
Documentary filmmaker Stanley Nelson says Till's murder served as a catalyst for supporters of civil rights.
"All those people who are about his age, you are about 14 in 1955, then became the front ranks of the civil rights movement," said Nelson.
Cohen wrote a play about Emmett Till and for years has joined other civil rights leaders and lawmakers in trying to memorialize him on Capitol Hill.
"Out of this bitterness, this bitter fruit of our history, can come these beautiful things we can do," said Cohen. "Make a difference, speak up."
Cohen hopes this young American Sycamore Tree will keep Till's memory alive.