  A classical result says that a free action of the circle $\Bbb{S}^1$ on a
topological space $X$ is geometrically classified by the orbit space $B$ and by
a cohomological class ${H}^{^{2}}{(B,\Bbb{Z})}$, the Euler class. When the
action is not free we have a difficult open question:
  $\Pi$ : "Is the space $X$ determined by the orbit space $B$ and the Euler
class?"
  The main result of this work is a step towards the understanding of the above
question in the category of unfolded pseudomanifolds. We prove that the orbit
space $B$ and the Euler class determine:
  * the intersection cohomology of $X$,
  * the real homotopy type of $X$.
