The Nádasdy Mansion is a Neo Gothic style manor house designed by István Linzbauer and Alajos Hauszmann situated on 24 hectares in Nádasdladány, Hungary. It dates from 1873 to 1876, and belonged to the Nádasdy family. It was used for the exterior of the vampires' mansion in the Underworld film series.
The ancestors of the Nádasdy family had estates in the area as early as the 14th century. The Counts of Schmidegg acquired the estate in Ladány in 1736. Leopold Nádasdy bought the mansion from Károly Schmidegg in 1851, the name of which was later changed to Nádasdladány at the request of the family. Leopold then established the new headquarters of his estates here.
Wikipedia https://en.wikipedia.org/wiki/Nádasdy_Mansion
Coordinates 47°8'4.205" N 18°14'29.428" E