Complex sentence: When it opened in 1997, it was the tallest roller coaster in the world, and its speed of was tied for the fastest with Tower of Terror II, a similar roller coaster which opened two months earlier at Dreamworld in Australia.
Split into simpler sentences: When it opened in 1997, it was the tallest and joint fastest roller coaster in the world. It is similar to Tower of Terror II, which opened two months prior at Dreamworld in Australia.