A little hiking, a little history, and great views make for a great day out, and Cannon Fort fits the bill! I went during COVID times, so the little restaurant at the top was closed, but overflowing boxes and bins of empty beer bottles indicated the locals were still really enjoying the sunsets here, which are supposed to be the best on the island.

Cannon Fort was maintained by the French in the early 20th century to defend the Haiphong harbor, and the two eponymous cannons there are both French from 1910. The structures and tunnels, however, were built by the Japanese during WW2, when they overran Vietnam. Later it was taken back by the Vietnamese, taken back by the French, taken back by the Vietnamese, and actually stayed in use throughout the Vietnam War. Apparently 6 American planes were actually shot down from here, and there’s still an active military base and airport you will get shooed away from as you walk up the hill beyond the entrance.

The uphill walk from Cat Ba town only takes perhaps half an hour or 40 minutes, but it’s steep enough to be a real workout. Sometimes there’s a guy at the gatehouse who charges each person 30,000; sometimes the gate is just open. There’s a place to park a motorbike. Once there, exploring takes an hour or hour and a half max; it’s a closed circuit with absolutely no chance of getting lost.

I recommend stopping by Casa Bonita afterwards for food and drinks; it’s on the way if you’re walking from Cat Ba town, and one of my favorite restaurants on the island.