As the town residence of the Grand Duke, the grand-ducal palace has unquestionably one of the most beautiful façades in the city (Flemish Renaissance, 16th century). Majestical interior and splendid above stairs (with light design by Ingo Maurer) can be visited exclusively during summer. https://www.visitluxembourg.com/en/place/castle/palace-of-the-grand-dukes