A legation was a diplomatic representative office of lower rank than an embassy. Where an embassy was headed by an ambassador, a legation was headed by a minister. Ambassadors outranked ministers and had precedence at official events. Legations were originally the most common form of diplomatic mission, but they fell out of favor after World War II and were upgraded to embassies.
Courtyard of the U.S. Legation in Tangier, Morocco
The Old Korean Legation Museum in Washington, D.C.
A diplomatic mission or foreign mission is a group of people from a state or organization present in another state to represent the sending state or organization officially in the receiving or host state. In practice, the phrase usually denotes an embassy or high commission, which is the main office of a country's diplomatic representatives to another country; it is usually, but not necessarily, based in the receiving state's capital city. Consulates, on the other hand, are smaller diplomatic missions that are normally located in major cities of the receiving state. As well as being a diplomatic mission to the country in which it is situated, an embassy may also be a nonresident permanent mission to one or more other countries.
Spanish embassy to the Holy See and the Sovereign Military Order of Malta in Rome
Embassy of the United States in Helsinki, Finland
House of Sweden featuring Swedish as well as Icelandic and Liechtenstein diplomatic missions to the United States.
Embassy of Argentina, Beijing, China