Headquarters of the United Nations be sent by courier. The United Nations Postal Administration issues stamps, which must be used on stamped mail sent from the building. For award purposes, amateur radio operators consider the UN headquarters a separate "entity" under some award programs such as DXCC. For communications, UN organizations have their own internationally recognized ITU prefix, 4U. However, only contacts made with the UN Headquarters in New York, and the ITU count as separate entities. Other UN organizations such as the World Bank count for the state or country they are located in. The UN Staff Recreation Council operates amateur radio station 4U1UN,
Headquarters of the United Nations which was a gift from the Luxembourg government Other prominent artworks on the grounds include "Peace" - a Marc Chagall stained glass window memorializing the death of Dag Hammarskjöld - the Japanese Peace Bell which is rung on the vernal equinox and the opening of each General Assembly session, a Chinese ivory carving made in 1974 (before the ivory trade was largely banned in 1989), and a Venetian mosaic depicting Norman Rockwell's painting "The Golden Rule". A full-size tapestry copy of Pablo Picasso's "Guernica", by Jacqueline de la Baume Dürrbach, is on the wall of the United Nations building at