NPR's Eric Weiner examines the problem of culturally accepted racism in one of the world's most homogeneous nations — Japan. Even today, foreigners make up a relatively small percentage of the country's population. And it's not uncommon to see signs in windows proclaiming that businesses are for "Japanese Only." But as more immigrants continue to flow into the country, calls to end discrimination are growing. (5:21) ) Check out more commentaries and comprehensive NPR News coverage of the UN World Conference Against Racism.