Before World War II began, it seemed unlikely that the communist nation led by Joseph Stalin would be aided by the United States. But as early as 1940, President Franklin Roosevelt sought to improve relations, viewing Hitler’s Germany as the greatest threat to world peace.

During World War II, all the republics of the former Soviet Union suffered catastrophic casualties. Official figures say 26.6 million Soviet citizens died, including 8.7 million military personnel, the largest loss of life among the allies combating the Axis powers.

Although the United States was still formally neutral when the 1941 Lend-Lease Act was approved, the law allowed it to become what Roosevelt called the “arsenal of democracy” by sending military supplies to those fighting Nazi Germany. The Soviet Union became the second-largest recipient of U.S. aid — the British Commonwealth received the most — getting $11.3 billion worth of munitions and other materials, including industrial equipment, raw materials, clothing and food.

(State Dept./McCann)

The shortest and safest route for the aid was from the U.S. state of Montana through western Canada to Alaska, and then on to Siberia and Moscow. The 12,700-kilometer (7,900-mile) journey became known as the Alaska-Siberia Route. But it badly needed infrastructure to support the effort. The second route began in Florida, stopped in North Africa, then Iraq, and ended in Moscow. This route was 20,900 kilometers (13,000 miles).

The United States constructed seven airfields in central Alaska between Northway and Nome, while Canada built six between Edmonton and Whitehorse. The airfields were built or upgraded every 160 kilometers (100 miles) or so from Edmonton, Alberta, to Fairbanks, Alaska. They also were linked on land by the Alaska Highway project.

In 2006, U.S. and Russian officials commemorated this vital supply line and wartime cooperation at the dedication of the Lend-Lease Monument in Fairbanks, Alaska. As part of the 70th anniversary of the end of World War II, the nonprofit organization BRAVO 369 Flight Foundation announced it is recreating the flight path from Montana to Moscow with American and Russian pilots, using vintage aircraft.