Initially stimulated by the predictions of high resolution LCDM simulations (e.g. Millennium and Aquarius) and then dramatically advanced by scrutinizing large digital imaging data sets such as SDSS, Pan-STARRS, and  the Dark Energy Survey, our picture of the Milky Way and its satellite population has dramatically changed in the past decade. After an overview of our historical understanding of the Milky Way and its dwarf galaxies  I will reflect over the tremendous progress in the emerging field of ultra-faint stellar systems, present the most fascinating results we were able to obtain and discuss the new mysteries waiting for us to be solved in future research.

This colloquium is partly supported by the BK21 Plus of Chungnam National University.