https://en.wikipedia.org/wiki/Takabisha
https://en.wikipedia.org/wiki/Kingda_Ka
http://www.mnn.com/green-tech/transportation/stories/the-10-scariest-roller-coasters-in-the-world
http://www.torontosun.com/2014/06/25/worlds-craziest-roller-coasters
http://www.travelandleisure.com/slideshows/10-scariest-thrill-rides-on-the-planet/10
https://www.wired.com/2014/05/scariest-themepark-rides/
http://www.stratospherehotel.com/Activities/Insanity
https://en.wikipedia.org/wiki/The_Smiler_(roller_coaster)