The bricks of the Very Large Telescope Interferometer

In this talk we will perform a review of the basic principles of the optical/near-infrared interferometry and of the current European facilities to use this observational technique. Particularly, we will describe the interferometric observables used at near-infrared wavelengths. We will provide a review of the current (and future) instruments available at the ESO Very Large Telescope Interferometer (VLTI), their advantages and limitations as well as, the typical science cases to be addressed with them.  Finally, we will provide a general frame of the current software available for VLTI data analysis.