Aix-la-Chapelle in 1818, but persisted for over a century until after World War II, when the rank of ambassador became the norm. In between that time, figures such as the German Chancellor Otto von Bismarck were renowned for international diplomacy. Diplomats and historians often refer to a foreign ministry by its address: the Ballhausplatz (Vienna), the Quai d'Orsay (Paris), the Wilhelmstrasse (Berlin); Itamaraty (Brasília); and Foggy Bottom (Washington, D.C.). For the Russian foreign ministry, it was the Choristers' Bridge (Saint Petersburg) until 1917, while "Consulta" referred to the Italian foreign ministry, based in the Palazzo della Consulta (Rome) from 1874 to 1922. Immunity The sanctity of diplomats has long been observed, underpinning the modern concept of diplomatic immunity. While there have been a number of cases where diplomats have been killed, this is normally viewed as a great breach of honour. Genghis Khan and the Mongols were well known for strongly insisting on the rights of diplomats, and they would often wreak horrific vengeance against any state that violated these rights. Diplomatic rights were established in the mid-17th century in Europe and have spread throughout the world. These rights were formalized by the 1961 Vienna Convention on Diplomatic Relations, which protects diplomats from being persecuted or prosecuted while on a diplomatic mission. If a diplomat does commit a serious crime while in a host country he or she may be declared as persona non grata (unwanted person). Such diplomats are then often tried for the crime in their homeland. Diplomatic communications are also viewed as sacrosanct, and diplomats have long been allowed to carry documents across borders without being searched. The mechanism for this is the so-called "diplomatic bag" (or, in some countries, the "diplomatic pouch"). While radio and digital communication have become more standard for embassies, diplomatic pouches are still quite common and some countries, including the United States, declare entire shipping containers as diplomatic pouches to bring sensitive material (often building supplies) into a country. In times of hostility, diplomats are often withdrawn for reasons of personal safety, as well as in some cases when the host country is friendly but there is a perceived threat from internal dissidents. Ambassadors and other diplomats are sometimes recalled temporarily by their home countries as a way to express displeasure with the host country. In both cases, lower-level employees still remain to actually do the business of diplomacy. Espionage Diplomacy is