The Castle can be visited
Blauer Hof Castle

Laxenburg's Blauer Hof Palace in Lower Austria is a historical structure distinguished by its architectural evolution and its connection to the Austrian nobility.
History+
The Blauer Hof was first documented in 1544 as a free court, with Melchior Arguello named as its initial owner. Between 1710 and 1720, the building underwent extensive expansion under Imperial Vice-Chancellor Friedrich Karl von Schönborn, executed by architect Lucas von Hildebrandt. The estate owes its name to an earlier owner, Sebastian von Ploenstein (Blauenstein). After several changes of ownership, including Count Adolf Metsch and members of the Counts Daun, the Blauer Hof came into the possession of Maria Theresia in 1762.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Maciek Wegrzyn
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 48.0683, 16.3583