Complex sentence: Since the festival closed, the site passed through the hands of a series of developers, from the late 1980's to the mid- 1990s the Festival Hall was used as the Pleasure Island amusement park.
Split into simpler sentences: Since the festival closed, the site passed through the hands of a series of developers. From the late 1980's to the mid- 1990s the Festival Hall was used as the Pleasure Island amusement park.