The Eiffel Tower contributed to the capture of Mata Hari.
During WW1, the French military used the tower's wireless station to intercept enemy messages from Berlin. In 1914, the French were able to organise a counter-attack dyring the Battle of the Marne after secretly learning that the German Army was halting its advance.
Three years later, the station atop the Eiffel Tower intercepted a coded message between Germany and Spain that offered details about 'Operative H-21'. Based in part on this message, the French arrested, convicted and executed Mati Hari for spying on behalf of Germany.
