More than 47 million people observed 9/11 last year by taking time to help others through charity and volunteer work. This year, organizers of 9/11 National Day of Service and Remembrance estimate 50 million Americans will take part in 9/11 Day.

Organizers are encouraging Americans to share their volunteer plans on social media for what they say will be the largest social media tribute ever. Lessons plans for teachers, volunteer opportunities and information on the large scale volunteer service projects happening in New York City, Washington, DC, Phoenix, Miami, Boston, Los Angeles, Ft. Lauderdale and Dallas are available online at 911Day.org. A list of charities honoring the victims of Sept. 11 is available at Parade.