You should really cite your source when using something that was not written by you as text or images not made by you, even if the original text was written in another language. Translating whole articles and posting them 1:1 without citing a source is even worse as it is considered plagiarism as you are essentially pretending that the post is really written by you while you just translated it probably even with the help of automated translations service such as Google Translate. What you are doing here is just giving every Russian person out there a bad reputation...

Source in Russian: http://www.kidslibrary.ru/content/21-sentyabrya-mezhdunarodnaya-noch-letuchih-myshey