Lüneburg's appeal is largely in the walking: the medieval Altstadt is compact and almost entirely car-free in the core. The big draws are the three brick-Gothic churches — St. Johanniskirche on Am Sande, St. Michaeliskirche where the young Bach sang, and St. Nicolaikirche down by the river — and the leaning houses of Auf dem Meere between them.
The old salt quarter clusters around Am Sande and the Stintmarkt waterfront, with the historic Alter Kran and the Salt Museum giving the city its narrative context. For wider views, climb the 1907 Wasserturm or walk up the Kalkberg, the gypsum stub of the old castle hill, just west of the centre. North of the centre, Kloster Lüne holds a remarkable collection of medieval embroidery in its old refectory.
If you have a second day, the Lüneburger Heide heathland to the south is the obvious excursion — best in August when the heather is in flower.