In the early '80s Hammer started as a bus cleaner with a Dutch
public broadcaster and worked his way up from there. He eventually became production assistant, taught himself how to be a video editor, and turned director and
producer, working on some of Holland's biggest productions with
Joop van den Ende. In subsequent years Hammer was involved with the introduction of private radio and TV
RTL in the Netherlands and Belgium, owned a trucker radio station and was advisor to media moguls such as
Leo Kirch (Kirch Gruppe). After his career in radio and TV, Hammer turned author in 2006, publishing his first book,
Satans Lied (Satan's Song). It is a story about one of the most bizarre
art thefts in history, that of a panel of
Jan van Eyck's
Ghent Altarpiece. The book was published in various countries and languages, among which German, French, Polish (
Tajemnica Oltarza Gandawskiego), Turkish and English (
The secret of the sacred panel). Subsequent books were specifically aimed at the Dutch market and not translated into other languages; but in 2012 Hammer published a controversial book,
The hunt for the Nazi Gold, secrets of the March Impromptu Code revealed. It describes an investigation into a document, drafted at the end of
World War II by
Martin Bormann, that allegedly contained directions to locate Hitler's personal diamonds and a stash of Nazi gold. These items were hidden somewhere in the Bavarian mountains and intended to finance the terror group
Werwolf. Hammer's book received worldwide attention and for some time he, just like another hunter, Leo Giessen, led various expeditions, mostly near
Mittenwald. The expeditions remain unsuccessful and no diamonds or gold have been retrieved. == Photography ==