Virtual Observatory: Scientific exploitation of astronomical archives.

The Virtual Observatory (VO) group at CAB (http://sdc.cab.inta-csic.es) has a long experience in the development and operation of astronomical archives. Already in 1998 LAEFF was selected to host INES, the archive and data distribution system of the IUE satellite. The VO group is also the core of the Spanish Virtual Observatory (SVO, http://svo.cab.inta-csic.es), a project that is part of the International Virtual Observatory Alliance (IVOA http:/ / www.ivoa.net) since June 2004 and that coordinates the VO initiatives at national level and acts as a contact point for the international VO projects. The Spanish Virtual Observatory is the framework where, thanks to an innovative research methodology and a powerful suite of analysis tools, it is possible to tackle astronomical projects that, outside VO, would have been impossible to carry out.