<P> In the face of modern warfare , digging in was standard practice by the start of WWI . To attack frontally was to court crippling losses , so an outflanking operation was the preferred method of attack against an entrenched enemy . After the Battle of the Aisne in September 1914 , an extended series of attempted flanking moves , and matching extensions to the fortified defensive lines , developed into the `` race to the sea '' , by the end of which German and Allied armies had produced a matched pair of trench lines from the Swiss border in the south to the North Sea coast of Belgium . </P>
<P> In the face of modern warfare , digging in was standard practice by the start of WWI . To attack frontally was to court crippling losses , so an outflanking operation was the preferred method of attack against an entrenched enemy . After the Battle of the Aisne in September 1914 , an extended series of attempted flanking moves , and matching extensions to the fortified defensive lines , developed into the `` race to the sea '' , by the end of which German and Allied armies had produced a matched pair of trench lines from the Swiss border in the south to the North Sea coast of Belgium . </P>
when were the first trenches dug in ww1
when were the first trenches dug in ww1
by the start of WWI
by the start of WWI