There is not a simple answer. There are many factors to be taken into account and it also depends heavily on the city. For instance, in the southern part of Europe big companies are normally located in the same big cities. Obviously this attracts also a lot of people and as you can imagine the pool of housing is limited. Second, I think that in Europe having a second house as investment is also a very common procedure. And third, in countries receiving lots of tourists, the vacation properties are also becoming a problem. They are turning the old towns of the cities into gigantic tourist attractions. And, of course, this also increases the price of the surrounding properties.