Complex sentence: It is Seger's only Number 1 album to date, spending six weeks atop the Billboard 200, and knocking Pink Floyd's massive-selling "The Wall" from the top spot.
Split into simpler sentences: It is Seger's only Number 1 album to date, spending six weeks atop the Billboard 200. It was the album that knocked Pink Floyd's massive-selling "The Wall" from the top spot.