Every so often I read about the large amount of unexploded ordinance in France and Belgium from WWI - this morning I looked for more information and ran across this Wikipedia page:

In the Ardennes region of France, large-scale citizen evacuations were necessary during UXO removal operations in 2001. In the forests of Verdun French government "demineurs" working for the Department du Deminage still hunt for poisonous, volatile, explosive munitions and recover about 900 tons every year. The most feared are corroded artillery shells containing chemical warfare agents such as mustard gas. According to the film "Aftermath", these demineurs "have gathered more than twenty million shells but have lost six hundred demineurs. At the current speed, France will be fully cleared and safe - in seven hundred years." French farmers still find many UXOs when ploughing their fields; the so-called "iron harvest."

Seven Hundred years - the mind boggles. History isn't as far removed as many people seem to think.