Why were the trenches in World War 1 bad and smelling?

Answer 1

In Gallipoli, the trenches were only about 1/2 a metre wide, while the Turkey soldiers were shooting at them day in, day out. it was muddy, there were fleas, lice and maggots on the floor and millions of flies that landed on everything. the smell of the dead was horrific, and your mates were ether firing back at the Turkey soldiers, or lying down dead or wounded.

Answer 2

Trenches where smelly because of all the built up water, urine, and feces. They were also bad do to these problems, the soldiers stood in the wet ground all day, which caused there feet to prune up (like being in a bath for to long) which then caused there skin on their feet to become fragile and soft, causing their shoes to scrap the skin off their feet. With these open wounds the water then infected the foot, it eventually moves up the legs to a major artery and kill the soldier.