That fascinating building above the Clark Adam square is not else but the Buda Castle. If you would like to know what kind of "treasures" are hidden in the Castle, then there are some description below.
The grassy roundabout on the Buda side is the so-called Clark Adam’s square. The square got the name after a Scottish engineer.In a small patch garden, you can see the 0 kilometer stone which is an elliptical sculpture.
Once you are on the top, what to see?
The Turul: This is our national bird that is guarding the gateway to the Royal Palace. It is a bronze bird, wings are outstretched with a sword in its talons.
Sándor Palace: It is a Neoclassical building built-in 1806. Now, this houses the offices of the President of the Hungarian Republic. Two bells are have been set up here. They are working every day at noon. Also here you can see the change of the guardian's ceremony.
Hungarian National Gallery: The Gallery is housed in the former palace’s main wing. The permanent collection : -Ground floor: Mediaeval lapidarium, a collection of stone fragments recovered from medieval and Renaissance Buda and elsewhere in Hungary. -First floor: 19th-century painting, Mediaeval and Baroque collection. -Second floor: 20th-century painting and art of the 1930s
Széchenyi Library: The library is placed in the Ybl wing of the palace. It faces away from the river. The Széchenyi library keeps copies of all works published in the country. There is a corridor that is lined with an exhibition of documenting the history of the palace.
Budapest History Museum: The first-floor display Budapest’s defeat in the 2nd World War. The oldest exhibits can be found underground in the former cellars. You can visit the tall lookout Tower and a bastion with gun placements. The museum is opened between 10am-6pm. On Mondays, the museums are closed.
You should spend a whole day upon the Castle Hill to visit everything. It can be a good family day also.