A Description of Russian
Russian is a language of fantastic literature, music, and more. Furthermore, it a language of great utility for studying just what has happened in much of the world during the past couple hundred years. Many Russian language sources remain untranslated into English (and other world languages). Russian has a long written history and there many other related languages you can study (e.g. Slavonic) which will be easier with a command of Russian.
Russian uses the Cyrillic script. As with the Western European languages, the art of typography is quite developed for the Cyrllic script (used with Russian, Mongolian, and other languages. As such, you can enjoy beautiful texts, carefully typeset (c.f. Chinese language websites you have to zoom in to view, only a handful of font choices). Unlike the other European languages with funny accent marks, its default keyboard layout is pretty decent (see a heatmap of the standard layout).
I very much like the sound of the Russian language. One special feature of Russian is that there is a lot of palatalization, which manifests as y sounds everywhere—that combined with many "reduced vowels" (more on this below) make Russian a very "smooth" sounding language. For me this was lots of fun because the languages I have the most experience studying (East Asian languages, Spanish) are rather choppy languages with relatively simple syllable structure.