The Alaska Highway stretches for over 2,000 kilometres, running from Alberta, across the Rockies, through the Yukon, and all the way into Alaska. This extraordinary highway has been called "one of the greatest engineering feats of modern times." But it wasn't built by Canadians; it was built by the United States army after the Japanese attacked Pearl Harbour. It allowed Americans to send supplies and weapons by land rather than by sea to Alaska and also to help the Russian Army who were fighting the Nazis. After the war the highway was turned over to Canada. It brought many changes to the north, and today it is a popular tourist destination.