By Pierre Kosmidis
Research by Tony Allen
The Bulgarian steamship Knyaguinya Maria Luisa was bombed by British aircraft at the entrance to Piraeus harbour on May 30th, 1941.
Her deck cargo of benzine in drums caught fire and this detonated her cargo of munitions.
The ship blew up with an explosion that sank three ships in the harbour and caused some 200 casualties.
 Hocking C., Dictionary of Disasters at Sea during the Age of Steam
 Rodger Haworth, Miramar Ship Index