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
Circuit of the Americas of Silverstone's Maggotts-Becketts-Chapel sequence, Hockenheim's arena bends, and a replica of Istanbul's Turn Eight. Other corners were loosely inspired by the Senna 'S' at Interlagos and the Österreichring's Sebring-Auspuffkurve. A feature of the circuit is a deliberate widening of corners, to encourage drivers to follow multiple racing lines. A similar feature was used at the Buddh International Circuit in India, where the circuit widens on the approach to certain corners. The circuit was one of only a handful on the Formula One 2012 calendar to be run counter-clockwise, the others being Marina Bay, the Korea International Circuit, Yas Marina, and