Complex sentence: Erebus is a four-story haunted attraction located in Pontiac, Michigan, and held the Guinness World Record for largest walk-through haunted attraction from 2005 until 2009.
Split into simpler sentences: Erebus is a four-story haunted attraction located in Pontiac, Michigan, and it is one of the world's largest walk-through haunted attractions. Erebus held the Guinness World Record for largest walk-through haunted attraction from 2005 until 2009.