Famous painting representing e.g. a primarily calamitous ruin (8)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Anagram (re-presenting = rearranging) of EG + A + first letter (primarily) of C [alamitous] + RUIN . Extended definition: a painting by Picasso in response to the 1937 bombing of the town of Guernica.