Complex sentence: Until the hypercoaster Wild Thing (the fifth highest and fastest roller coaster in the world at the time it opened in 1996), Corkscrew was the only outdoor all-steel roller coaster in Minnesota.
Split into simpler sentences: Until the hypercoaster Wild Thing (the fifth highest and fastest roller coaster in the world at the time it opened). In 1996, Corkscrew was the only outdoor all-steel roller coaster in Minnesota.