These 17 photos show Finland's brutally cold World War II battle with the Soviet Union

Farther north, another battle raged in the unprecedentedly cold winter of 1939-1940, as outnumbered Finnish forces took on the Soviet Union.

The two countries signed a nonaggression treaty in the early 1930s, but that did not allay Finnish concerns about its neighbor. Those fears were justified. The Soviet Union surged across the Karelian Isthmus on November 30, 1939.

About a million Soviet troops crossed into the dense forests and frozen expanses that connected the two countries, but determined Finnish troops turned the bucolic landscape into a charnel house for underprepared, underfed, and overwhelmed Soviet troops.

Finland is thought to have lost about 25,000 soldiers during the 105-day conflict, while the Soviets lost nearly 200,000 troops, with hundreds more stricken by frostbite.

Helsinki eventually succumbed, however, signing a peace pact on Moscow's terms on March 12, 1940 — though Finland did not completely capitulate and would later partner with Germany to fight the USSR.

As the photos below show, the Finnish troops made deft and deadly use of a vicious winter and unforgiving landscape to exact the maximum toll from Russian invaders.

The war between Finland and the Soviet Union started at 10:45 p.m. local time on November 30, 1939. Here are trenches that were dug in Helsinki, seen on December 1, 1939.

A house hit by a Russian aerial bomb in Helsinki, seen on December 11, 1939. It was still on fire after several days. Heavy Soviet artillery barrages could reportedly be heard in the Finnish capital — more than a hundred miles from the front.

Source:

Some of the 50 volunteers for the Finnish army preparing to sail from New York to their native country on December 9, 1939, on the Swedish-American liner Gripsholm.

Finnish soldiers on the roads near the Mannerheim defensive line against Russia during the fighting in the Karelian Isthmus, Finland, on December 14, 1939.

A Finnish soldier at his post on the Mannerheim Line in Finland on December 14, 1939.

The war came to have two forms: A conventional conflict that revolved around the Mannerheim Line — Finnish fortifications on the Karelian Isthmus — and a campaign of harassment and attacks waged by Finnish ski troops against Soviet personnel in the country's forests.

A private car destroyed by a bomb during the first aerial bombardment of the Finnish capital of Helsinki in 1940. Women members of the volunteer corps soon began dismantling the wreckage and removing it from the street.

A Finnish light artillery squad on patrol duty in the Karelian Isthmus on January 3, 1940. Using white tunics over their heavy winter clothing as camouflage, the soldiers took on the appearance of ghosts as they traveled over the snow-covered terrain.

The Finnish troops often had to improvise and augment their snow gear with bed linens for camouflage. But they were effective: Thousands of Soviet troops, mostly dressed in auspicious and inadequate khaki uniforms, disappeared into the wilderness.

A Soviet bomber, shot down by Finnish antiaircraft guns on the Karelian front on January 3, 1940, where Russia was reporting massing seven divisions for a drive on the Mannerheim Line.

Ski patrols like this, seen somewhere in northern Finland on January 4, 1940, were credited with successes that led to reported Russian routs at points where Finnish "suicide patrols" penetrated into Soviet territory.

White suits for camouflage ski poles, skis, and rifles make these men look like explorers, but they’re Finnish soldiers setting out, hunter style, to worry the Russians, in the snows and forests of Finland on January 10, 1940.

Finnish troops reporting the capture of a Russian tank in the snow-covered forest on the Eastern Front on January 10, 1940. The Russians lost more than 300 tanks in the first month of the Russo-Finnish war.

What a bullet began, the Arctic cold finished, for this Russian soldier who died near Suomussalmi, Finland, shown on January 31, 1940. He was killed while erecting a field telephone line. The extreme cold froze the soldier in this position.

The bitter cold could subject living flesh to frostbite within minutes of exposure, and dead bodies were often frozen to the firmness of bricks.

Finnish troops sometimes capitalized on the ghoulish brutality of the conditions, positioning dead Soviet troops in upright poses meant to intimidate their adversaries.

Members of a Finnish ski patrol examining the tomb of two Russian officers on the Salla front in Finland on February 10, 1940. The tombstone is a painted red box with a Soviet star made of coins nailed on the box.

While the Fins would eventually settle for a peace deal with the Soviets, the resistance exacted a heavy toll on Stalin's armies.

"

Finnish soldiers looking over the battleground at Suomussalmi, Finland, on February 10, 1940, after Russian troops had been back. The frozen bodies are dead Russians.

A Swedish volunteer, "somewhere in Northern Finland," protecting himself from the subzero arctic cold with an eerie mask on February 20, 1940, while on duty. The small holes in the mask are what the soldier sights his rifle through.

Simo Häyhä, who was known as "the White Death," was a Finnish sniper credited with killing more than 500 enemy troops within 100 days during the Winter War.

Häyhä's military career was ended by a shot to the face that blew off part of his cheek and lower jaw. He survived to become a Finnish hero, dying of natural causes in 2002.

Canadian volunteers who were fighting for Finland seen February 24, 1940. They needed to learn to ski to prepare themselves to attack the Russians on snow-covered battlefields.

Finnish soldiers, members of one of the ski battalions that made a stand against Russian troops, seen with their reindeer on March 28, 1940, as they took the road back to the new Finnish border set in the Soviet-Finnish peace pact.

These 17 photos show Finland's brutally cold World War II battle with the Soviet Union

JOIN OUR PULSE COMMUNITY!