Its last private owner was Sarah Aurelia Halasz, morganatic widow of a prince, who lived there with her family. The owners sold the palace in the 1970s and today is a luxury five star boutique hotel after extensive renovations. The palatial hotel has 33 suites and it was the venue for the controversial Iran nuclear deal signed on 14 July 2015. On a trip along the Ringstrasse, you pass the Vienna State Opera, the Museum of Art History and its counterpart, the Museum of Natural History, the Parliament, the Burgtheater, and the City Hall. Right in the heart of the city, the Gothic St. Stephen’s Cathedral casts its shadows through narrow cobblestone streets. The palaces and parks of the Habsburg era – Schönbrunn Palace with the Gloriette and the zoo, Belvedere Palace, and the Hofburg palace – give the city an imperial air, enriched by beautiful buildings from the Art Nouveau period.