How to thank civil right African American Activist for their work?

To be honest I don't think this is worth stressing over you get to meet a great person who did a lot to make this future I think the best thing you could do is stay respectful and just say it if you feel the need to. Thank you so much. It doesn't hurt if you do your research on that specific person if you want to ask about specific events they were involved in

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof

its whatever your mind tells you