By the start of the 1970s, efforts by Jackie Stewart saw several Formula One events cancelled because of safety concerns. For the 1969 event, Armco barriers were placed at specific points for the first time in the circuit's history. Before that, the circuit's conditions were (aside from the removal of people's production cars parked on the side of the road) virtually identical to everyday road use. If a driver went off, he had a chance to crash into whatever was next to the track (buildings, trees, lamp posts, glass windows, and even a train station), and in Alberto Ascari's and Paul Hawkins's cases, the harbour water, because the concrete road the course used had no Armco to protect the drivers from going off the track and into the Mediterranean. The circuit gained more Armco in specific points for the next two races, and by 1972, the circuit was almost completely Armco-lined. For the first time in its history, the Monaco circuit was altered in 1972 as the pits were moved next to the waterfront straight between the chicane and Tabac and the chicane was moved further forward right before Tabac becoming the junction point between the pits and the course. The course was changed again for the 1973 race. The Rainier III Nautical Stadium was constructed where the straight that went behind the pits was and the circuit introduced a double chicane that went around the new swimming pool (this chicane complex is known today as "Swimming Pool"). This created space for a whole new pit facility and in 1976 the course was altered yet again; the Sainte Devote corner was made slower and a chicane was placed right before the pit straight.