Decorated and furnished with priceless works of art the State Rooms are regularly used by The Queen and members of the royal family for State entertaining, official ceremonies and investitures. In addition to the 19 State rooms there are 52 royal and guest bedrooms, 188 staff bedrooms, 92 offices, 78 bathrooms and a 36m long, 18m wide and 13m high Ballroom.
The State Rooms are open to the general public most days between June and October each year. Before the present-day flat front was built onto Buckingham Palace the inner courtyard was 'open' on the eastern side facing The Mall.
Marble Arch, moved in 1851 to the top of Park Lane, was originally placed on this open eastern frontage as the official ceremonial entrance. Traditionally only members of the Royal Family and the King's Troop, Royal Horse Artillery, were allowed to enter the palace through the arch.