Hundreds of people move from Mexico to the U.S. every day, fewer return. Technological, economic and political changes have made migration and particularly immigration an increasingly dynamic issue at home and abroad. It has taken on intense significance in Europe as the European Union relaxes borders between its member states, cracking open once-isolated communities and increasing diversity by orders of magnitude. This sixty-eighth edition of OASE, an independent, international journal of architecture, urban design and landscape design, considers the impact of migration on cities from an architectural perspective. It looks at the effect of migration on urban development and the use of space, and on social and cultural issues of identities, subcultures, territories, and tolerance.