Intensity interferometry removes the stringent requirements on mechanical precision and atmospheric corrections that plague all amplitude interferometry techniques at the cost of severely limited sensitivity. A new idea we recently introduced, very high redundancy, alleviates this problem. It enables the relatively simple construction (~1cm mechanical precision) of a ground-based astronomical facility able to transform a two-dimensional field of point-like sources to a three-dimensional distribution of micro-arcsec resolved systems, each imaged in several optical bands. Each system will also have its high resolution residual timing, high quality (inside each band) spectra and light curve, emergent flux, effective temperature, polarization effects and perhaps some thermodynamic properties, all directly measured. All the above attributes can be measured in a single observation run of such a dedicated facility. We conclude that after three decades of abandonment optical intensity interferometry deserves another review, also as a ground-based alternative to the science goals of space interferometers.Subject Heading: instrumentation: interferometers -instrumentation: high angular resolution -techniques: interferometric 1. INTRODUCTION Amplitude interferometry is today's mainstream technique for high angular resolution astronomy, mainly in the infrared regime. In principle, amplitude interferometers combine the electromagnetic waves from two or more separate locations to produce a high-resolution brightness distribution, or image, of the source. Intensity interferometry, on the other hand, combines the intensities of the electromagnetic wave via the correlation of the electrical currents generated by the detectors of the already-detected intensities. For astronomical purposes, the main advantage of intensity interferometry is its mechanical robustness: the required mechanical accuracy depends on the electrical bandwidth of the detectors, and not on the wavelength of the light. This opto-mechanical robustness also means that the atmosphere does not influence the performance of the instrument. The main disadvantages of intensity interferometry are its very low intrinsic sensitivity and the fact that the classical, two-detector intensity interferometer cannot reconstruct the phase of the complex degree of coherence, and thus can't be used to produce true images [1].