That Req Square shot near the bottom - they are standing next to the so-called "Kremlin Wall", which was the honorary burial place back in Soviet times. Slightly over 100 people are buried there, lots of politicians obviously, but also scientists, war heroes and, notably, cosmonauts - Gagarin, Komarov (killed in crash-landing in '67), Dobrovolski/Patcaev/Volkov (killed when the landing capsule vented air while still in space), and I think several more.

That's the reasons for the photo. Paying tributes to those died in space expeditions.