Thousands of trees will be planted at the Flight 93 Memorial in Shanksville this weekend.
The annual tree-planting event is part of a major reforestation effort that will eventually result in 150,000 new trees at the Memorial.
The trees commemorate the passengers and crew of United Flight 93 and remembers all of the lives lost on September 11, 2001.
This year, a team of more than 500 volunteers will plant an additional 20,000 seedlings, over 30 acres of land.
