If you're traveling by train or bus, you'll most likely pass through Passerelle. This terminal is a major transportation hub for the area and an attraction in itself.
You can keep your wallet safely tucked away, because it won't cost a thing to explore Passerelle. Located in Gronn, you'll find some interesting attractions not far from this transportation hub. Why not check out Notre-Dame Cathedral, Grand Ducal Palace and National Museum of History and Art too?