No popular holiday for today, but there are plenty of observations.
On the neo-pagan wheel of the year (in the north, in the southern hemisphere, this would be the same observation on Feb 5, as the days grow shorter at the end of summer), this holiday is called Lammas or Lughnasadh. The former is a contraction of “loaf mass” the latter from Celtic I believe. Regardless, it’s an early harvest festival (hence the loaves).
It commemorates the dropping of “little boy” on Hiroshima in 1945, although previously “the device” had been detonated on July 16 1945 on Pueblo territory on Turtle Island (aka New Mexico, USA). The Spanish had named the desert stretch Jornada del Muerto, meaning the one day’s journey of the dead man (or words to that effect).
This is definitely a festival worth reviving (because the lame attempts made here in Canada at naming holidays is just weak. “Family Day” and “Civic Holiday” are my two favourites).