https://creativecommons.org/publicdomain/zero/1.0/https://www.rawpixel.com/image/7665416Edit ImageSaveSaveEditCropCustom TextUSSR 1931-05-15 registered (no. 391) airmail cover sent from Moscow to Berlin. Franked on the first day of issue with the imperforate Zeppelin set.Original public domain image from Wikimedia CommonsMorePublic DomainFree CC0 image for Personal and Business useInfoView CC0 LicenseJPEGSmall JPEG 1200 x 982 px | 300 dpiLarge JPEG 3500 x 2866 px | 300 dpiBest Quality JPEG 3547 x 2904 px | 300 dpiFree DownloadUSSR 1931-05-15 registered (no. 391) airmail cover sent from Moscow to Berlin. Franked on the first day of issue with the imperforate Zeppelin set.More