The Imperial crown jewels of Iran (also known as the Imperial crown jewels of Persia) include several elaborate crowns and decorative thrones, thirty tiaras, and numerous aigrettes, a dozen bejeweled swords and shields, a vast number of unset precious gems, numerous plates and other dining services cast in precious metals and encrusted with gems, and several other more unusual items (such as a large golden globe with the oceans made of emeralds and the latitudes and longitudes marked in diamonds) collected by the Iranian monarchy from the 16th century (Safavid dynasty) on. The collection is housed at The Treasury of National Jewels (the official name) but is known colloquially as the Jewellery Museum. It is situated inside the Central Bank of the Islamic Republic of Iran on Tehran's Ferdowsi Avenue. The Imperial crown jewels of Iran are the largest set of displayed jewels in the world that are in state ownership in one location. The museum is open to the public from 14:00 to 16:30 hrs except on Wednesday, Thursday and Friday. The museum has onsite guides with knowledge of Persian, English, French and Russian languages.