Population synthesis studies promise an independent story of time evolution if we can reach the main sequence in Virgo. The suggested volume also includes enough examples to provide a "fair sample" of stellar populations. A 30 meter aperture is needed to do a complete study in a finite time (still years, however). High angular resolution is necessary to obtain accurate photometry and uncontaminated spectra of individual stars in a large sample of clusters in a large sample of galaxies, to study the history of element build up in the Universe and the constancy (or not) of the initial mass function.
