When I started collecting stamps in 1987, this is one of my first censorship covers I ever received. It is not a very special one but for me it has been the start to my favorite topic of my favorite hobby.
Italian letter from Merano/Italy controlled by German censorship in occupied South Tyrol. Letter could not be sent to the addressee in St. Moritz/Switzerland and was therefore forwarded to Zurich by Swiss express.
Swiss domestic tax up to 250g = 20 Rp. (1.1.1921-31.10.1967) plus express surcharge for letter mail up to 1kg = 40 Rp. (1.3.1934-31.12.1946)