Disorientating, disconcerting and deeply daring, this high-adrenaline ride has to be one of the all-time most terrifying coasters. After a steep climb backwards, riders are dropped from 200 feet (61m) nearly straight down. The four-by-four seats, which are arranged on either side of the track, spin independently, adding an extra dizzying dimension. Another standout feature of the '4th dimension' coaster is its so-called 'raven turns' – half loops that change their mind midway and become sheer drops. Add to that a pounding soundtrack and fire effects, and this is one extraordinary ride.