In mid-April, the pre-dawn breeze at Ypres was gentle, and the humid sea breeze still carried a chill.
Inside the Allied front, most soldiers were still asleep, with only a few sentries yawning while keeping watch towards the Germans' direction from their trench.
Suddenly, a yellow-green smoke wall, taller than a person, rose from no-man's-land and slowly drifted towards the Allied frontline with the wind.
Felix, who was on guard, rubbed his eyes, thinking he was seeing things due to a lack of sleep.
After repeatedly confirming it, he turned and asked his comrade Klein, who was dozing off with a rifle in his arms: "Klein, wake up. Am I seeing things? A yellow-green fog."
Klein mumbled: "You must be mistaken. The weather's been great these past few days; there wouldn't be any fog!"
"It's real, right in front of us." Felix kicked Klein: "Get up and take a look."
