Created in 1993, the Organization of World Heritage Cities (OWHC) has been given a mandate by the United Nations to protect the cultural, historical, and social heritage of the world's great cities. For a number of years, the organization has worked towards this goal by publishing helpful "how to" materials for any number of interested parties, including city officials, heritage groups, and concerned citizens. Recently, this site was created in an attempt to bring these materials together at one online destination. On this site, visitors can learn about case studies (such as those designed to rehabilitate the urban core of Havana), read publications on how to preserve the built environment, and peruse a list of related links. The publications area is quite strong, as it contains a number of introductory works such as "A History of Architectural Conservation" by Jukka Joklehto and "Standards in Preventive Conservation" by Rebeca Alcantra.