Some of what the other ppl are recommending are not what I would recommend for Intermediate learners... Only because of the complexity of the vocabulary and narrative style, I don't want you to become frustrated and give up... So I want to suggest another route: Rius. Its a comic about the history of Coca-Cola. The author is a Mexican activist and is very political... He has many other books on Marxism, the Spanish Revolution, The Spanish Conquista, Religion, etc... It's still tough, but the subject matter is very interesting and the pictures (deceptively, simple line drawings) help get his message across.