Braunschweig's historic core is compact and almost entirely walkable. The Burgplatz is the centrepiece — a medieval square containing the cathedral, Dankwarderode Castle, and the famous bronze lion (the original, cast in 1166, is inside the castle; the outdoor one is a 19th-century replica). The atmosphere in the evening, especially when lit, is among the finest in Lower Saxony.
The Herzog Anton Ulrich Museum (closed Mondays) holds one of Europe's oldest public art collections: Vermeer's Girl with a Wine Glass, Rembrandts, Cranach, Holbein, and an exceptional applied arts collection. The city's other museum worth serious time is the Braunschweigisches Landesmuseum, which covers the regional history from the Welf duchy to the present.
For a different angle on the medieval period, walk north from Burgplatz through the lanes of the Magniviertel — the oldest surviving quarter of the city, its half-timbered houses largely intact despite the wartime bombing of the wider city. The Altstadtmarkt square, five minutes west, has the Gothic town hall and the church of St Martin opposite.