6 Best Sights in Cat Ba Island, Halong Bay and North-Central Vietnam

Home to 32 species of mammals, including the endangered white-headed langur monkey, which lives among the jungle terrain and freshwater lakes, Cat Ba National Park covers about 263 square km (101 square miles) of Cat Ba Island. Within its tropical rain forest are 78 species of birds and 20 species of reptiles. In addition to impressive beaches and mangroves, within its boundaries are two historical caves once used as clinics during the Vietnam War. Signs outside the park offer four hiking routes; 1, 2, and 3 cost 40,000d, and 4, the Cang Viet Hai Trail, costs 80,000d. Active travelers can tackle this demanding (yet rewarding) 18-km (11-mile) trail across the park if they arrive before 10 am. For a striking vista of the surrounding scenery, the view from the park's observation tower is hard to beat. Be warned, though, the climb-up metal ladders and cliffs are not for the faint of heart. The park is about 30 minutes from Cat Ba Town.

One of the most intriguing sights on Cat Ba Island, Hospital Cave served as a bomb-proof medical facility during the American War. It also provided well-hidden refuge for Vietcong leaders and fighters during the conflict. Like Cu Chi Tunnels in the south and Vinh Moc Tunnels near Dong Ha, Hospital Cave is a prime example of the Communists' engineering ingenuity. Built between 1963 and 1965, the three-story facility is a labyrinth of dim chambers. Guides operate from outside the cave, which is around 10 km (6 miles) north of Cat Ba Town and will show you around the 17 rooms and point out notable features such as the old operating theater and a natural cavern that was used as a movie theater.

Although it is technically and geologically an extension of Halong Bay, the 300 or so karst islands of Lan Ha Bay feel somewhat removed from tourist traffic. Lying south and east of Cat Ba Town, they are too distant for most of the tour boats that leave from Halong City to reach. Therefore visitors here, mostly on itineraries arranged in Cat Ba Town, can enjoy the sense of peace and isolation that Halong Bay has arguably lost. Sailing, snorkeling, and kayaking are popular activities here. Lan Ha Bay also possesses several idyllic beaches such as Hai Pai Beach (also known as Tiger Beach), and day tours are cheap, starting at 360,000d.

A French-era fort that was also used during the defense of Haiphong during the war with the United States, this hilltop landmark is also notable for offering some of the best views on Cat Ba Island. A motorbike taxi can take you most of the way up the hill from Cat Ba Town and wait while you explore the area. You will find two cannons, two bunkers, a small photography and memorabilia shop, and several lookout points that offer views of the sweeping vista that captures the karst-studded landscape in all its glory. There is also a small café serving tea and juice where you can relax if you've made the journey on foot.

The island's beaches are among the best in North Vietnam and the three stretches of sand at Cat Co Cove are justifiably popular with Vietnamese tourists and other sun-worshippers. Of the three beaches, the one at Cat Co 2 is the prettiest with limestone cliffs backing golden sand. Here, you will find Cat Ba Beach Resort, one of the island's more luxurious lodgings. The other two beaches are less crowded, but there tends to be more debris and trash in the water. Cat Co is an easy 15-minute walk from Cat Ba Town. Amenities: food and drink; parking; toilets. Best for: swimming; sunset.

Many overnight boat tours will take you to see one or more of the four floating villages on Halong Bay, where 300 local families make a living by fishing the mystical waters. If they're not fishing or fixing their nets for the next big catch, they may be passing the time swinging on hammocks—or even rowing toward your cruise boat to sell you groceries and souvenirs in a floating "store." These impressive fishing villages have their own wooden shacks and grocery stores that stay afloat by Styrofoam platforms wrapped in waterproof tarps.