If you have an interest in WWII, there’s an amazing museum in Diekirch , just a short distance from Lux City. After the Battle of the Bulge, farmers gathered up the equipment, vehicles, uniforms, etc. that had been left in their fields. Eventually they moved it all to Diekirch into this museum. It’s filled with life-size dioramas … rooms full of artifacts … a parachute hanging from the ceiling … and letters & photos on the walls from soldiers who had fought in the battle. We found it fascinating.
All public transportation is free in Luxembourg. If you take the train or bus to Diekirch, you’ll likely change in Ettelbruck, which is a lovely little town worth exploring.
Other interesting places in Luxembourg are the Family of Man photographs, now on permanent display in a chateau in Clervaux. And the lovely castle in Vianden.
We loved Luxembourg and got so busy exploring the beautiful countryside that we never even made it into Luxembourg City.