Gentrification is the arrival of wealthier people in an existing urban district, which leads to increased rents and property values and changes to the district's character. It often displaces poorer communities. Characteristics of gentrification include an increase in median income and property prices in the area, as well as changes to the types of housing and businesses. Effects can be both positive, like reduced crime and vacancy rates, and negative, such as loss of affordable housing and displacement of long-time residents. Examples of gentrified cities include areas of London, Mexico City, and neighborhoods in Canada, France, South Africa, Italy, Poland and Russia.