
The photo shows an activist (hippie with a pipe for smoking) face to face with a soldier with his rifle.
This picture I like because, first, shows the spirit of the time: social protest, demonstration, discontent and desire for social change around the world. It also shows the disposition against the fear, in this case, there is no fear to the order forces.
And second, there is a direct ideological confrontation and world view between the activist and soldier. Shows the polarization experienced in the crisis: social emancipation (defiant activist) and conservative: the man (soldier) oppressed.