Four days works well for Hanoi, giving enough time to properly explore the Old Quarter's density while still fitting in at least one major day trip to the surrounding region. Days 1 and 2 stay within the Old Quarter and its immediate surroundings. Hoan Kiem Lake sits at the centre, with the photogenic Huc Bridge leading to Ngoc Son Temple on a small island — a natural anchor for wandering the surrounding 36 streets, each traditionally named for the trade once sold there. Spend your evenings on a guided street food walk if it's your first visit; a knowledgeable guide on night one gives context for everything you'll eat unguided for the rest of the trip, from bun cha to the city's famous egg coffee. Day 3 covers Hanoi's modern political history. The Ho Chi Minh Mausoleum complex includes his preserved body (viewing requires respectful dress and queuing, and the mausoleum closes certain days for maintenance — check current hours), his modest stilt house nearby, and the One Pillar Pagoda. The Temple of Literature, Vietnam's first national university, rounds out the day with a quieter, older layer of history. Day 4, if your schedule allows a longer trip, is best spent at Halong Bay or Ninh Binh, both reachable as a long day trip but genuinely better as an overnight extension. The limestone karst scenery at either spot is unlike anything in the city, with Halong Bay better known internationally and Ninh Binh offering a quieter, less crowded alternative with similar landscapes. For those staying in the city instead, Train Street — a narrow residential street with train tracks running directly between the houses — remains a popular and slightly surreal stop, though check current train schedules and access rules, since this has changed periodically as authorities balance safety with tourist interest. A few practical notes: crossing the street in Hanoi takes a specific technique — walk at a steady, predictable pace and let the motorbikes flow around you, since stopping suddenly is more dangerous than continuing forward. Carry cash, as many street food stalls and smaller shops don't accept cards. And if booking a Halong Bay cruise, research the operator rather than booking the cheapest option on arrival, since quality varies considerably across the many companies running similar routes.