There are many historic building of note. Blacket planned the 1854 watch house; the old post office, now a restaurant, is even earlier, dating from 1850.
William Belmain was a First Fleet surgeon who verbally crossed swords with John MacArthur and was challenged to fight the entire New South Wales Corps' officers one by one. Satisfaction was reached before it came to duelling.
The nine lakes attract many species of water birds, and the six-sided Federation monument - is the only one of its kind. It is possible to ride through the park on hired horses or bicycles.
The quay is the hub of the harbour ferry services, and large cruise ships - including Queen Elizabeth II - tie up at the international terminal where thousands of migrants have taken their first steps on Australian soil.
Dwarfed by neighboring office blocks, the sandstone Customs House stands where Phillip raised his flag. Above the entrance is a portrait of Queen Victoria and a splendidly carved coat-of-arms. The anchor of Phillip's ship, HMS Sirius (which was of less tonnage than a Manly ferry), is in a nearby square.
Much more visible to the public is the almost as grand stables and servants' quarters, since 1916 the Conservatorium of Music. Built to Francis Greenway's design in 1821 on Governor Macquarie's orders, its basic structure resembles a castle keep, with the courtyard since roofed in to form the auditorium. Its extravagance at a time when the colony was almost bankrupt angered the London government.
Completed in 1932 after nine years' work, the steel are is a majestic feat of engineering. Its weight of 60,000 tonnes rests on four bearing set on immense concrete foundations, and at its highest point the steelwork is 134m - equivalent to 40 storeys - above the water.
Construction was carried out from each end and when the two halves met they were only 7cm out of alignment. Despite a toll on the 40 million vehicles which cross the bridge each year, the 9 million borrowed for construction is still not paid.
Now the park is 16ha of formal gardens, with the State's war memorial standing among trees and lawns. The granite art deco tribute rises 30m and comprises a Hall of Memory and a Hall of Silence where statuary symbolises Sacrifice.
The largest of three fountains, the Archibald Memorial, is a bequest of Jules Francois Archibald, co-founder of the Bulletin and founder of the annual Archibald Prize fro portraiture.
Archibald was an ardent Francophile, and the memorial, bequested for in his will, commemorates the associaton of Australia and France during World War I.
It was known as Queens Cross over the turn of the century, than the name was changed to avoid confusion with Queens Square near Hyde Park.
The core of colonial buildings on the eastern side is Sydney Hospital, built in the 1880's on the site of the famous Rum Hospital, given its name after Governor Macquarie in 1810 accepted a tender which, as payment, allowed the builders the monopolistic right to import 45,000 gallons of spirits.
One wing of the Rum Hospital has, since 1829, been the home of the New South Wales Legislature, while the other wing, with a history as the Royal Mint and various government offices, has been renovated to be a fine arts museum.
Across the street bewigged barristers emerge form the tower of the new Law Courts. Among the statuary is a bronze of King Edward VII by Thomas Brock, whose best-known work is the Queen Victoria Memorial outside Buckingham Palace.
The oldest and most striking building on the plaza is the massive pile of the General Post Office, an example of the Classical Revivalism of Victorian times at its most magniloquent.
Architect James Barnet is one of many heads carved into the friezes. The colonnaded frontage stretches for 120m, while the 70m tower was the highest structure in the city centre in pre-skyscraper days.
The State's National Trust operates out of a two-storey building which, when taken over in 1974, was Fort Street School. Governor Macquarie had it built in 1815 as a military hospital.