This story was told to me by my uncle, who was a civil engineer and owner of a successful consulting company until he retired a few years ago.
Like most engineers, he is a very no-nonsense (almost nerdy) person, definitely not the superstitious type, nor the type to tell tall tales.
When my uncle was a teenager, his family lived in Nanking, China, a few years after the end of World War II. Some of you may recall that in 1937, Nanking was the site of what historians call the "Rape of Nanking" -- during the Japanese occupation of that city, it's estimated that half a million civilians were tortured and executed (civilians were frequently tied to poles and used by troops for target practice or bayonet practice, others were burned alive, buried alive, beheaded, run over by tanks, and subjected to numerous other atrocities too appalling to describe here), and some 200,000 women of all ages were brutally raped by Japanese soldiers -- although the exact number will never be known since most of the bodies were dumped into rivers and ponds or buried in mass graves and bulldozed over. If there was ever a city ripe to be haunted by the restless spirits of the dead, Nanking is it -- you can imagine the kind of psychic pain that probably lingers over that city.
Anyway, for a (very) short period of time, the family lived in a house in central Nanking that had been occupied by Japanese officers during the war. My uncle tells me that, every night, the family could hear the sound of a woman sobbing in the attic, although there was no earthly explanation for the sound, and the sobbing would continue all night until dawn, leaving the entire family terrified and sleepless. On occasion shortly after moving in, my uncle (as the oldest boy in the family) had to move some boxes into the rarely used basement, and took a candle with him down the steps (no flashlights in post-war China). When he reached the bottom, he put down the box and, looking around, saw several dark blotches on the concrete walls of the empty basement. As he stood there, he swears that the blotches began glowing an eerie phosphorescent blood red, and not from the light of the candle -- it was as if some kind of light were coming from the stains themselves -- and he realised to his horror that he was looking at glowing bloodstains from the Japanese occupation. A second later, the flame on his candle suddenly extinguished. Needless to say, he dropped the candle and ran from the basement screaming and slammed the door behind him and never ventured down there again until the family moved out after only living in that house for a few days.