It is reported that when Imam Hussein (AS) was killed not only the residents of the heavens cried for Imam Hussein (AS), but even the skies cried for him and they wept blood for this Mazlum. This is reported not only in the Shi'a books but also in the most important Sunny references:
“On the day of the martyrdom of al-Hussein (AS) the sky rained blood . . . .”
Thakhaa'er al-Uqba pp 144, 145, 150.
Al-Sawaa'eq al-Muhriqah pp 116, 192 . . . . . .
“There was not a stone which was not lifted but underneath it was found blood . . . ”
Al-Sawaa'eq al-Muhriqah pp 116, 192.
Tathkirat-ul-Khawaas p 284,
Tafsir ibn Kathir vol. 9, p 162 . . . . .