Leisurely walk around the lake and cross to Ngoc Son Temple to feel Hanoi's historic heart; best to go before late afternoon crowds. (Ngoc Son open ~8:00am–6:00pm.)
Explore the Hue Imperial Citadel (opens ~8:00am–5:30pm) to see palaces, gates and the Forbidden Purple City ruins — essential for central Vietnam history.
Join a morning tour to the Cu Chi Tunnels (depart early, site open ~7:00am–5:00pm) to explore wartime tunnel networks and try the demonstration shooting range.