*Abstract:* Branching processes are classical models in probability theory, that describe the evolution of a population over time. They play a key role in various areas such as random graphs, queueing theory or the analysis of algorithms.I will present in this talk several results, some classical, some more recent, on the behavior of branching processes when the population is large. In this regime, the discrete branching processes can be approximated by continuous ones, which are referred to as scaling limits.