Residence/office of the Ottoman sultan.
In the Ottoman Empire, the sultan would appoint a grand vizier to head the government. Just as the prime minister of Great Britain resides at 10 Downing Street, the grand vizier of the Ottoman Empire lived and worked in the Sublime Porte. This term is a French translation of al-Bab al-Ali, which means literally "the High Door." In the nineteenth century, it became common to refer to the entire Ottoman government as "the Sublime Porte," as it is common today to refer to the U.S. government as "the White House."