It really depends on the what you enjoy. Lux definitely has lots to offer for people with different interests. General Sightseeing - Visiting the Grund (Um bock), city center, Place d'armes, Duke's palace, Place Guillaume are a few spots. read more
Other Options - You can bike around the city/ take a Segway tour on a sunny day. I would also recommend recommend spend half a day visiting the countryside (Any one of the following Schengen/ Remich/ Diekirch/ Vianden) is also pleasant. read more
Brussels to Luxembourg and Bastogne Private Full-Day Trip. Start your day trip with a pickup from your central Brussels hotel or alternatively, meet your private guide in the center of town. Hop inside your luxury minivan and relax on the journey south to Luxembourg, the small, land-locked country that lies two hours away. read more