The house museum. It is not large, but very cozy, the taste and luxury of the owners are conveyed only by the ceilings, and the small decoration of the rooms... the remains of paintings,.... most of the relics were looted by the Nazis during the Second World War, the Soviets did the same .... half-empty rooms are depressing... and reflections... in general, a pleasant place.
I was there in 2011. I liked absolutely everything from Byzantine icons of the 11th century to paintings by Rembrandt, Durer and Diego Velazquez da Silva.
I really liked the netsuke collection. There are many strong paintings - there are two or three in each hall, in front of which you want to stand for a long time… A good description of the halls and works. Very positive impressions! I will be happy to come again.
The museum that taught me that mysterious things turn out to be in plain sight. Just walk past Bosch into the next room and look at Velasquez.
And there are also very good, thoughtful, musical events.