Okay, first of all - this isn´t exacly an "urban legend" it´s more like the typical european ghost story.
So, from 1618 - 1648 the "thirty years´War" http://en.wikipedia....irty_Years'_War raged in Germany and devastated wide areas. Like many others, the town where I grew up was completely depopulated. The special condition about my home town is the large system of red sandstone caves running all underneath it - those caves where used during wartimes as shelter for the population. During the thirty years´War, however they had been used as an amunition depot. The legend tells, that a huge amount of the stored ammuntion there went off, burying lots of people. After the war, the caves were forgotten for several centuries - until theyr rediscovery in the late 19th century. During WWII they were -once again- used as a shelter or bunker system. Many of the people seeking shelter during the last War told storys of strangly antiquated clothed people they saw in the caves wandering around and suddenly dissapear from one moment to the other. About 10 years ago, the caves were renovated and closed off parts were reopened for visitors. During the works a part was reopened, that apparently had been closed off during a large scaled structural collapse ... the workers didn´t believe their eyes when the found the remains of almost 60 corpses - all from the time of the thirty years´War.
Im sorry if my English might be a bit "shaky" in this post ^^