Slide 1 of 4, Soldiers wearing gas masks during World War One, Poisonous gas was used as a weapon The First World War was the first-time poison gas was used on a large scale during war.

MADRID - A vast archive of letters sent by relatives of soldiers missing in World War One seeking the help of Spain's King Alfonso XIII in finding them has been published online for war historians ...

A vast archive of letters sent by relatives of soldiers missing in World War One seeking the help of Spain's King Alfonso XIII in finding them has been published online for war historians and ...