Heroes' Square (Hősök tere) is a landmark in Budapest, and was built to commemorate the 1,000th anniversary of the foundation of the Hungarian state, in 1896. The square is surrounded by the statues of 14 prominent figures from Hungarian history, while the archangel Gabriel stands on top of the central column. This statue was awarded the grand prize at the 1900 Paris World's Fair.
Citadella at the top of Gellért Hill is another Budapest landmark. The view is amazing: you can see Buda Castle, the Parliament building, the bridges over the Danube, the Pest side and the Buda Hills, all from one place.
And of course, you cannot forget the Chain Bridge, which was the first permanent bridge between Buda and Pest over the River Danube.