Where they are usually evident?

-The first major trench lines were completed in late November 1914. At their peak, the trenches built by both sides extended nearly 400 miles from Nieuport, on the Belgian coast, to the Swiss border. Among the Allies, the Belgians occupied 40 miles, the British occupied 90 miles and the French occupied the rest.

- In total the trenches built during World War I, laid end-to-end, would stretch some 25,000 miles 12,000 of those miles occupied by the Allies, and the rest by the Central Powers.