Complex sentence: Throughout the 1990s and into the early 2000s, the Thekla was taken over and run as an underground nightclub, becoming a cornerstones of Bristol's drum & bass music scene.
Split into simpler sentences: Throughout the 1990s and into the early 2000s, the Thekla was taken over and run as an underground nightclub. It quickly became one of the cornerstones of Bristol's drum & bass music scene.