Circuit de Monaco downhill again to a double right-hander called "Portier," named after region of Monaco, before heading into the famous tunnel, a unique feature of a Formula One circuit. (Until 2009 only one other circuit, Detroit in 1982–88, featured a tunnel, but the F1 series now includes racing at the Yas Marina Circuit in Abu Dhabi, which presents a shorter tunnel at the exit of the pit lane.) As well as the change of light making visibility poor, a car can lose 20–30% of its downforce due to the unique aerodynamic properties of the tunnel. The tunnel also presents a unique problem
Autodromo Enzo e Dino Ferrari at Imola was named after the nearby state) and it also hosted the 1980 edition of the Italian Grand Prix, which usually takes place in Monza. When Formula One visits Imola, it is seen as the 'home circuit' of Ferrari and masses of "tifosi" (Ferrari supporters) come out to support the local team. Imola, as it is colloquially known, is one of the few major international circuits to run in an anti-clockwise direction. (Istanbul Park, Korea International Circuit, Marina Bay Street Circuit, Autódromo José Carlos Pace, Circuit of the Americas, and the Yas Marina Circuit are other anti-clockwise circuits used