The Top 10 CNN Heroes of 2009 — remarkable individuals nominated by viewers for their sacrifices and accomplishments — are being announced today on CNN.

CNN's Anderson Cooper will reveal one Top 10 CNN Hero each hour starting at 1 p.m. ET, with the final honoree to be revealed at 10 p.m. The announcements will be made at the top of each hour on CNN, CNN.com and CNN.com Live.

The daylong event culminates with a special edition of "AC360," profiling this year's honorees and their causes. "Change the World, You Vote, CNN Heroes" will air at 11 p.m. ET Thursday on CNN and CNN International.

The year 2009 marks CNN's third annual global search for everyday individuals changing the world. Since February, the network has aired weekly profiles of CNN Heroes, chosen from more than 9,000 nominations submitted by viewers in 100 countries.

A panel comprised of luminaries recognized for their own dedication to public service selected this year's Top 10 CNN Heroes. The blue ribbon panel includes humanitarians such as retired four-star Gen. Colin Powell, philanthropist Wallis Annenberg and Sir Elton John.

Each of this year's Top 10 CNN Heroes will receive $25,000 and will be honored at "CNN Heroes: An All-Star Tribute," airing from the Kodak Theatre in Hollywood on Thanksgiving night.

The global broadcast, with Cooper as the host, will culminate with the announcement of the CNN Hero of the Year, selected by the public in an online poll that begins at 11 p.m. ET Thursday.

Viewers can go to CNN.com/Heroes to participate in the poll, which continues through November 19 at 6 a.m. ET. The individual receiving the most votes will receive an additional $100,000.