WW1 - what was life like in the trenches?

What was life like in the trenches? 

• System of trenches - miles in every direction 
• A company of 240 soldiers were supposed to spend 6 days a month on the front-line but it often turned out to be months.
• Life in the trenches was boredom, uncertainty, discomfort and danger
  • Shells
  • Machine guns 
  • …