Du Bois mentions the terms "color line." Are there any color line issues in the 21st century? If so, please give some examples.
Good question! In Du Bois's quote, he specifically mentions the color line being the problem of the 20th century and references its existence in all parts of the world. The term itself refers to the division between races--a figurative line over which one race cannot cross.
I don't think that anyone could logically argue that color lines are now nonexistent, but in some places of the world, the lines are "fainter"--they don't have as much power as they one did. In the United States, for example, we undeniably still struggle with race relation issues, but the Civil Rights movement pushed through significant positive changes. While the movement and act did not obliterate the color line, they certainly made it less restrictive. Black Americans were able to cross the line into jobs that were previously "off-limits," and the desegregation of schools began.
That being said, we still see a great deal of self-segregation not just in America but also around the globe. Some Asian countries significantly discourage intermarriage, and my students still segregate themselves during lunch and for other activities. While neither example represents a mandatory color line, each at least demonstrates that for some reason we humans resort to "drawing" the lines.