The XMM/Megacam-VST/VIRMOS Large Scale Structure Survey
  The objective of the XMM-LSS Survey is to map the large scale structure of the universe, as highlighted by clusters and groups of galaxies, out to a redshift of about 1, over a single 8x8 sq.deg. area. For the first time, this will reveal the topology of the distribution of the deep potential wells and provide statistical measurements at truly cosmological distances. In addition, clusters identified via their X-ray properties will form the basis for the first uniformly-selected, multi-wavelength survey of the evolution of clusters and individual cluster galaxies as a function of redshift. The survey will also address the very important question of the QSO distribution within the cosmic web. 
M. Pierre (CEA Saclay)