The nuclear test-ban treaty signed by the united states, the soviet union, and great britain in 1963 stopped the testing of nuclear weapons in all locations, except
on land
underwater
in the atmosphere
underground
nextreset

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.