There are 1950s sci-fi films which reflect on the breakdown of society or even the end of mankind. But this is the first to show us what this might look like. A nuclear cloud has enveloped the earth killing nearly everyone, but leaving buildings intact. An African American (Harry Belafonte) was buried underground. When he digs himself out, he is alone in New York City.
Eventually the engineer encounters another survivor (Inger Stevens). Though they are the last people on earth, the conventions of the vanished society still limit their freedom. When a white male (Mel Ferrer) joins them, the acrimony is mostly motivated by masculine rivalry rather than race. Conflict is bred in the bone of mankind.
The events are interestingly compromised by censorship; a romance between the resourceful, charismatic black man and the blonde is forbidden. But while race is a factor in the balance of power between the three, sexual jealousy is more prominent.
The main attraction is the eeriness of Belafonte walking the Manhattan ghost town, and beginning a new life in its empty buildings. This would be copied many times but never improved on and the b&w CinemaScope captures the otherworldly emptiness of the metropolitan wilderness.