Complex sentence: In the 2010 Census, Atlanta was recorded as the nation's fourth largest majority black city, and the city has long been known as a center of African American political power, education, and culture, often called a black mecca.
Split into simpler sentences: In the 2010 Census, Atlanta was recorded as the nation's fourth-largest majority-black city. It has long been known as a center of African-American political power, education, and culture, often called a Black Mecca.