The palace rivals Versailles
"House," being a loosely used term here, but the Reggia di Caserta -- also known as the Palace of the Bourbon Kings -- was conceived by Bourbon King Charles III and designed to rival Versailles. It served not just as the royal home, but as a seat of government, and it maintains 1,200 rooms, a full theater, four 41,000sqft inner courts (that's almost a full football field without the end zones... each!), and 40 "monumental rooms" dedicated completely to frescos. Versailles, by comparison, has only 22. But the interior is only the beginning, as the Baroque architecture gives way to a 200-acre hunting park, highlighted by the Great Fountain where water flows down nearly 500ft over a sculpture of a bathing Diana being observed by Actaeon.