From Valencia, Calif.: A new investigation reveals severe injuries on a notable roller coaster. Two women experienced brain injuries so severe they required emergency surgery. The incidents happened in a short time frame, less than a week apart.

The roller coaster in question features rotating seats and intense sequences of flips. It is considered extremely thrilling and one of the most intense worldwide.

Further information about these incidents can be found through a report from CNN, including details about one of the riders, a 40-year-old woman visiting with her family.