Sunday marked the 10th anniversary of the Sept. 11, 2001, terrorist attacks in which 2,977 Americans perished as a result of plane crashes orchestrated by hijackers targeting New York City and Washington D.C.

While the horror and loss experienced on that day should not be forgotten, families of the victims of the attacks and support groups have long lobbied for a way to commemorate their loved ones through compassionate efforts as well.

After seven years, that goal was finally realized in 2009, the first year the September 11 National Day of Service and Remembrance was officially designated. The National Day of Service and Remembrance was established to honor those who perished on September 11, and to help renew the bonds of compassion and unity that were strengthened in the days after the terrorist attacks.

Now, each Sept. 11, volunteers across the country join hands to give back to their communities in various ways, such as clean-up and beautification projects, supporting food banks and honoring military veterans and first responders.

Yesterday, countless magazines, newspaper articles and television documentaries revisited the tragedies of 10 years ago. But the National Day of Service and Remembrance gives everyone the chance to make a positive impact no matter where they live.

According to HandsOn Network, a national volunteer organization, projects across the country were expected to unite more than 1 million Americans through various community-building opportunities this year.

Also on the 10th anniversary of the attacks, the National September 11 Memorial and Museum opened on the former site of the Twin Towers in New York City, where 2,653 perished in the crumbling buildings and on the ground, as well as hundreds of rescue workers.

A memorial at the Pentagon, the site of the third plane crash, which killed 184, was opened in 2008.

A fourth plane was intended to target Washington, D.C., but passengers on board helped overpower their hijackers and divert the aircraft to a field near Shanksville, Penn. Phase 1 of a permanent Flight 93 National Memorial for the 40 who died there opened on Saturday, one day before of the 10th anniversary of the attacks.

Photo credit: Amy Dreher / 911memorial.org