Headquarters of the United Nations themselves only, formally, at the request of the Secretary-General. Journalists, when reporting from the complex, often use "United Nations" rather than "New York City" as the identification of their location in recognition of the extraterritoriality status. The currency in use at the United Nations headquarters' businesses is the U.S. dollar. The UN's stamps are issued in denominations of the U.S. dollar. U.S. postal rates must be followed. The complex has a street address of United Nations Headquarters, New York, NY 10017, USA. For security reasons, all mail sent to this address is sterilized, so items that may be degraded can
Headquarters of the United Nations the complex opened in 1950, were expected to take about 7 years to complete. When completed the complex is also expected to be more energy efficient and have improved security. A temporary $140 million "North Lawn Building" was built to house the United Nations' "critical operations" while renovations proceeded. Work began on May 5, 2008, but the project was delayed for a while. By 2009 the cost of the work had risen from $1.2 billion to $1.6 billion with some estimates saying it would take up to $3 billion. Officials hoped the renovated buildings would achieve a LEED Silver rating.