Complex sentence: In 1981 the Twilight Zone, Toronto's first large dance club, opened in the area other clubs son followed and by the 1990s became home to one of the largest concentrations of night clubs in North America.
Split into simpler sentences: In 1981 the Twilight Zone, Toronto's first large dance club, opened in the area. Other clubs soon followed and by the 1990s, the area became home to one of the largest concentrations of night clubs in North America.