Complex sentence: For the following 25 years, the Museum featured paintings, rare books, photographs, and films of the African American experience, as one of the largest historical and cultural institutions west of the Mississippi River.
Split into simpler sentences: For the following 25 years, the Museum featured paintings, rare books, photographs, and films of the African-American experience. It was one of the largest historical and cultural institutions on African-American life west of the Mississippi River.