In this talk I will present the results from observations performed over the last two decades which have permitted us to determine the characteristics of all the ingredients involved in the formation process of high-mass stars, from scales of parsecs to scales of 100 AU. I start the journey presenting the characteristics of the parsec scale maternities (or massive dense cores, MDCs), then get along with the presence of filaments in MDCs, in particular their convergence giving rise to hub-filaments systems in advanced stages of evolution of MDCs. Then proceed with the characteristics of the fragmentation of MDCs in the earliest stages of evolution, leading to the formation of prestellar cores and streamers, and finally talk about the characteristics of HMYSOs and their associated components, such as disks and outflows, at the scales below 1000 AU.
