In the second half of the XX century, the understanding finally strengthened that the universe had a beginning — the Hot Big Bang theory was commonly approved. With the development of science, the accumulated data of astronomical observations and experimentally verified theoretical principles have allowed physicists to look into the past of the universe and create a reliable picture of its evolution. Start of construction of this picture was initiated by Alexander Friedmann who brought the dynamics in Einstein’s theory of gravity. Less than in ten years, the rate of expansion of the universe was calculated, being based on the results of observations. Next, there were a series of experimental and theoretical discoveries that allowed to reconstruct the sequence of events in the early universe in detail and to explain its observed homogeneity and isotropy as well as the structure formation and the abundance of chemical elements. However, these discoveries have put serious questions before the physics of elementary particles.