During the "dark ages", as named by historians, why did bridge engineering come to a halt?

Excerpt from w. e. b. du bois jon reese 4 du bois was one of the first male civil rights leaders to recognize the problems of gender discrimination. he was among the first men to understand the unique problems of black women, and to value their contributions. he supported the women's suffrage movement and strove to integrate this mostly white struggle. he encouraged many black female writers, artists, poets, and novelists, featuring their works in his crisis magazine and sometimes providing personal financial assistance to them. the cause was that w. e.b. du bois encouraged many black female writers, artists, poets, and novelists. what was the result? think about cause-and-effect relationships.

What former head of the cuban secret service was charged with protecting the country's prime minister for nearly 50 years?

Which of these effects of mass production techniques used during 1920