An old photograph from the Finnish Defence Forces' photo archive occasionally resurfaces on social media, largely because of how eye-catching it is. 

Taken by Finnish photographer Osvald Hedenström, the photo shows a type of camouflage used by Finland during World War II, to disguise the road from Soviet forces. The trees would not hide the road from aircraft, Atlas Obscura explains – but anyone looking a the area from a watchtower would see an uninterrupted line of trees. From ground level, of course, it looks like a lot of flying trees, which if anything is more suspicious than a road.

The Finnish made use of their natural resources – the fact that it is 75 percent covered by trees – to their advantage.

"The Finns didn’t have funds to buy artificial camouflage such as nets in vast quantities,” military historian at Finnish National Defence University Colonel Petteri Jouko explained to Atlas Obscura, “so they used trees, leaves, and foliage to confuse the enemy. They were accustomed to wilderness and took advantage of the forest, unlike the German soldiers operating in northern Finland.”

Trees were used to disguise everything from tanks to heavy artillery, while white sheets were used to disguise vehicles in the snow.

Finland allied with Nazi Germany while fighting the Soviets first in the Winter War, as the Soviets invaded in 1939, then during the Continuation War, an offensive advance by Finland and Nazi Germany on the Soviets from 1941-44. It was during the first few weeks of the Continuation War when Hedenström took a photo of the surreal sight of trees flying above the road.

[H/T: Atlas Obscura]