While chemical weapons have been used since the beginning of armed struggles, either for their flammable or toxic properties, it was only during World War I when what is known as "modern" chemical warfare began. July 28 marks the one hundred and one anniversary of the beginning of what is also known as "The Great War". This conflict created enormous consequences for society at the time, marking a before and after in the history of mankind, as well as being the genesis of modern chemical warfare.