  After recalling several constructions of the moduli space of curves of genus
zero by different people we give our alternative construction of the moduli
space. This gives a simple description of the intersection ring of this space.
We give a basis for the Chow groups and an explicit duality between the Chow
groups in complementary degrees. There is a recursive description of this
algebra by S. Keel. Our presentation is simpler in the sense that there are
fewer generators and fewer relations and our description is explicit.
