A family picks up trash on a beach near Toronto, Canada, as part of the 2012 International Coastal Cleanup.

Coca-Cola employees following a river cleanup in Atlanta, Ga. Last year, more than 24,000 Coke volunteers cleaned up 1,300 miles of coastline in 27 countries.

A young boy helps clean up a beach in Santo Domingo, Dominican Republic.

Volunteers serve as 'citizen scientists' by cataloging every item collected. Ocean Conservancy uses the data to produce the world’s only country-by-country, state-by-state index of the marine debris problem.