She appears to be standing across the Pripyat River from the V.I. Lenin Nuclear Power Station near Chernobyl, Ukraine S.S.R., sometime before 1:23 AM local time on April 26, 1986. Knowing Kronii's sense of occasion, probably not very long before 1:23 AM local time on April 26, 1986.
I made an account just to clarify this: CTM is NOT an abbreviation for "chuckling to myself"; it's a type abbreviation for "Conchetumadre" which is a slang/insult, that translates to "Your mother's pussy" (Since the word Conchetumadre in itself is an abbreviation of Concha de tu madre = Your mother's pussy) but it's used in a very similar way to "Motherfucker" in english.
Yeah, it isn't so much that WfM is the best show there is, or has the best characters. But what it represents. A dynamic change in the Gundam formula that I hope Bandai adopts more moving forward. I love Gundam the most when it decides to try something knew and be daring.
I looked at the source originally attributed to this image when uploaded here and realized they weren't the artist that drew it. I have edited this post so that the source leads to the artist's upload on Twitter, and changed the source link to reflect as such.