German troops supervise Belgian prisoners in the construction of a new line of trenches outside of Brussels in 1914. Note that the trenches are not dug in a straight line to prevent enemy troops, who seize a part of the trench, from firing the length of the defensive line. Forcing POW's to construct fortifications was a violation of the Hague Conventions. This photograph may have been retouched--note the prisoner in the foreground. He appears as a shadow of a sentry in other copies of this photograph.