National Portrait Gallery, Gripsholm castle (Gripsholms Slott), Mariefred, Sweden

The 14-year-old Christina as queen, painting by Jacob Heinrich Elbfas

en.wikipedia.org/wiki/Christina,_Queen_of_Sweden

In 1822, the building came to host the National Portrait Gallery (Sweden), which was placed under the supervision of the Nationalmuseum in the 1860s.
Between 1889 and 1894, the castle underwent a heavy and controversial restoration by the architect Fredrik Lilljekvist during which many of the 17th and 18th-century alterations were removed. The largest change was the addition of a third floor; the planned demolition of a wing did not take place.
Now the castle is a museum which is open to the public, containing paintings and works of art. Part of the castle houses the National Portrait Gallery (Statens porträttsamlingar), one of the oldest portrait collections in the world. The museum includes a badly-stuffed lion which has become infamous in recent years.