Trench warfare
The trenches had a terrible smell.  Bodies were rotting in shallow graves; men had not washed in weeks because there were no facilities; cesspits were overflowing; and creosol or chloride of lime was used to stave off the constant threat of disease and infection.  There was also the lingering odour of poison gas, and the smells of cordite, rotting sandbags, stagnant mud, cigarette smoke, and cooking food.  The smell was the first thing a new recruit would notice on the way to the front lines.  However, new arrivals soon got used to it, and eventually added their own body odor to the smell.