I am most familiar with slavery in the Western Hemisphere. All of the slave holding countries had a cash crop or financial reason for perpetuating slavery. Cotton, sugar, etc., were being produced in other countries, as well. The question still stands, why was the United States the only country that needed a war to end slavery.
Kevin, I'm really a little shocked by your response. You're a smart guy. Certainly you know that financial rewards for slavery were not unique to the U.S or the Southern states?