The former town palace of the Hanoverian Welf dynasty, on the bank of the Leine river at the western edge of the Old Town. Rebuilt after wartime destruction with a neoclassical riverfront porch designed by Laves and a thoroughly modern interior, it has served since 1962 as the seat of the Lower Saxon state parliament (Landtag).
Tours are run for free on most weekdays — book in advance through the parliament's website. The river terrace behind, with views across to the Beginenturm tower, is open at all hours.