One of the most intriguing and challenging quests of current astrophysics is to understand the physical conditions and processes that give rise to the formation of relativistic jets in AGN, production of high-energy particles, and emission of gamma-rays. Of particular interest is the question of how accretion onto super-massive black holes (SMBHs) generates such high-powered directed outflows. A combination of high-resolution very long baseline interferometry (VLBI) images with broadband flux variability measurements is a unique way to probe the emission mechanisms at the bases of jets. Our analysis of gamma-ray flux variability observed by Fermi-Large Area Telescope (LAT) along with the parsec-scale jet kinematics suggests that the gamma-ray emission has a significant correlation with the mm-VLBI core flux and the local orientation of the jet flow. In this talk, I will provide a brief overview of our current knowledge on high-energy emission from blazars. At the end of my talk, I will briefly highlight open questions and particularly promising avenues for progress.