People, taking a tour of a slum does not make you more enlightened. Intruding on the most base and private of human conditions with a camera does not make you more aware of foreign affairs. Yes, slums are full of poverty. Yes, they are a testament to a huge disparity of income (the one I worked in was next to my university, a school where wealthy Kenyans and foreigners attended). Yes, there is a lot of poop. They are also full of human beings. People who, despite stereotypes, go to school and get an education. People who are aware of the world. People who try their damned hardest to make something for themselves and their families. People who have feelings, who have dignity. People who are my friends.
If you want to help the world, educate yourself. I've got a million and one sources for you. Give to organizations that invest in local businesses and help raise employment. Learn about the charities you support. Legislate and advocate. And, if you're going to a developing nation, pick a program that honors the people and actually develop relationships once you're there. But please, please, please, do not go on a slum tour. People are not objects you can photograph to show others that you've "experienced" poverty. Poverty won't end until we see people as people. It certainly won't just because you toured a slum.