However, at 5:37 p.m. on August 29, 1907, just as the Phoenixville convention was wrapping up, the Quebec Bridge collapsed. The south anchor arm, cantilever arm, and half constructed suspended span all collapsed 150 feet into the St. Lawrence River in less than 15 seconds. The loss of life was relatively light with only two people killed that day. However, because of the unstable nature of the bridge, it took more than a month for investigators to determine what caused the collapse. The Quebec Bridge is an international bridge that connects Montreal, Quebec, with Pointe-Claire, a suburb of Montreal. It has three parallel spans over the Saint Lawrence River, each about half a mile long. The main span crosses from Montreal's Island South of the river to Pointe-Claire on the north shore. It is one of the world's longest cable-stayed bridges, with a length of 2.5 miles (4.0 km). Construction began in February 1905 and was completed in October 1908 at a cost of $7 million ($100 million in 2007 dollars). At the time of its construction, it was considered to be one of the most expensive public works projects in history. The bridge opened for traffic the next year on January 7, 1909. It was designed by Thomas Casey Jr. and Robert Montgomery Bird of the United States, and Henry Fox & Sons of London.