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 des Nations Circuit des Nations The Circuit des Nations ("Circuit of the Nations") is a long street circuit of 4110 meters between Lake Geneva and the Place des Nations in Geneva, Switzerland. It hosted the "Grand Prix de Nations", similar to a Formula One race; the "Grand Prix de Genève", similar to a Formula Two race; and various championship events. The first "Grand Prix de Genève" was held in Meyrin in 1931 and won by Marcel Lehoux, racing for Bugatti. The Geneva race-track was established between the lake (Geneva) and the Nations square. Its length was . Grand-Prix races were organised after