What made slums so difficult to live in?

Insecurity, poor living conditions, lack of hygiene, overcrowding.

Explanation:

Low neighborhoods is a concept of urbanism of the industrial society that arises with the growth of European cities in the nineteenth century, 1 which determines the social differentiation in the urban structure. It applies to the cities of any contintente.

It is used interchangeably with other expressions, such as marginal neighborhoods, poor neighborhoods, depressed neighborhoods, working neighborhoods or working-class neighborhoods, although each of them has a different nuance, marked by the intention of the speaker, between the pejorative, the dysfunctional, the problematic, precarious, even admiring. It is identified, therefore, with the social condition of its inhabitants, the lower classes, and not with the topographic altitude, although it may coincide (especially in the vicinity of ports or port neighborhoods). The name of working-class neighborhood is used as official place-name in neighborhoods of several cities. Despite the terminological similarity, it should not be confused with the Anglo-Saxon concept of downtown, which refers to the center of the city.

the space race was a battle to make advanced technology to get to the moon and to get a better understanding of space.