The grand entrance is a gate to an extensive garden surrounding a luxury First Republic (pre-war) villa, designed for Otto Petschek by architect Max Spielmann. Thanks to the business acumen of the Petscheks, a Jewish family originally from the town of Pečky, they became one of the leading European entrepreneurial and banking dynasties in the 19th century; their philanthropic activities were also notable. The villa was exceptional for its time in size (an incredible 148 rooms) and its modern facilities (including a fitness room and underground pool in the style of Roman baths). Since the end of the Second World War, the villa has been the property of the United States and serves as the American ambassador’s residence.
Source: https://www.prague.eu/en/object/places/2963/otto-petschek-villa