Built on remnants of an earlier settlement, Nizhny Novgorod’s magnificent kremlin dates to 1500–15 when Italian architect Pyotr Fryazin began work on its 13 towers and 12m-high walls. Most of the buildings are government offices, though the city's two most important museums are here as well as the 17th-century Cathedral of the Archangel Michael and a striking Monument to Heroes of WWII. You can walk the walls from May to November and take in riverside views.