What were the components of a trench? How were trenches protected?

Front line trenches were usually about seven feet deep and six feet wide. The front of the trench was known as the parapet. The top two or three feet of the parapet and the parados (the rear side of the trench) would consist of a thick line of sandbags to absorb any bullets or shell fragments. Soldiers also made dugouts and funk holes in the side of the trenches to give them some protection from the weather and enemy fire. The front-line trenches were also protected by barbed-wire entanglements and machine-gun posts. Short trenches called saps were dug from the front-trench into No-Man's Land.

Explanation:

uncle sam would be tossing and turning in his grave : *)