Is Race a Valid Concept?

Hotel Rwanda detailed the events of the nation of Rwanda from April to July of 1994. In April of 1994, Rwanda entered into a civil war, which sent ripples throughout the African nation. Within the first eight days over 8,000 innocent people had died as a result of the hostility that the Hutus (an Africa tribe contrived by the Belgians) had against the Tutsis (another contrived African tribe). The result of this mass genocide was close to a million people (937,000) dying simply because of a race that in all actuality did not exist. To explain, the Hutus and Tutsis were "tribes" that the Belgians created based on skin color, size of the head, and other irrelevant characteristics. It was a cultural conception meant to establish a division and thus maintain more power over the people that inhabited the country of Rwanda. My question to you is about this concept of race. Is race a cultural conception? Or is it a valid biological concept? Before you answer think about it first. We have been handed that we are a certain race for some time, many of the documents we fill out to apply for things have a section to denote your race so therefore we have always believe race to be valid. Many have used this as a means to make one race inferior to another. Also, think of who first developed this concept of race. Basically, try to look at this question from all angles.
To learn more about the Rwandan Genocide try some of the following links:
Rwandan Genocide
Rwanda 10 years after
Triumph of Evil