Invertigo is the name of an inverted shuttle roller coaster model developed and manufactured by Dutch company Vekoma. Four roller coasters based on this model were built, with the first installation opening in 1997 as HangOver at Liseberg amusement park located in Sweden. Three of the four are still in operation. Invertigo is designed as an inverted variation of their traditional Boomerang model, which first appeared in 1984. Invertigo's seat configuration is also a departure from its predecessor, in that riders sit back-to-back, resulting in all rows facing one another with the exception of the first and last.