A software tool for the investigation of plane loci. We describe the capabilities of Lugares for obtaining the equations and graphs of plane loci. Lugares is a Windows program written in Prolog that offers a standard dynamic geometry environment and uses the symbolic capabilities of CoCoA, a computer algebra system specialized in Groebner basis computations, or Mathematica. The main novelty in Lugares consists of the link between the dynamic geometry paradigm and a symbolic approach to automatic discovery in geometry. Through this link Lugares determines as a locus almost any algebraic curve specified by geometric conditions.