[Below: Here is an envelope from August 16, 1938, from Switzerland (Helvetia). This was sent to Athens, Greece where it was opened by the 'National Currency Protection Committee - Athens'. This was currency control, basically controlling the importation and exportation of Greek money.]

[Below: Back of envelope.]

[Below: Here is an envelope from June 16, 1942, from Switzerland (Helvetia). This was sent to Germany, where it was opened by censors (note censor tape) and examined by two agents (note the 371 and 336 stamps).]

[Below: Back of envelope.]

[Below: Here is an envelope from August 16, 1938 from Switzerland (Helvetia). This was sent to Hainichen, Saxony, where it was opened by censors (note censor tape). You'll note this censor tape is different than the one above. This one says 'OKW', this means Oberkomando der Wehrmacht (High Command of the Armed Forces). This tape is machine sealed and is rough to the touch. Also note the various censor stamps.]

[Below: Back of envelope.]

[Below: Here is a bonus envelope for you from WWI. It is from February 25, 1918 from Switzerland (Helvetia). This was sent to Tongeren, Belgium where it was opened by German censors (note censor tape).]

[Below: Back of envelope.]