2 Best Sights in Halong Bay and North-Central Vietnam, 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.

Established in 1962 by President Ho Chi Minh, Cuc Phuong National Park is Vietnam's oldest national park. Cuc Phuong consists of 220 square km (85 square miles) of heavily forested subtropical lowlands sheltering 97 mammal species, including nine species of civet, a kind of barking deer called the muntjac, as well as the extremely rare Delacour's langur. Approximately 336 bird species and 76 types of reptiles and amphibians live here as well, along with nearly 2,000 species of flora.

The Endangered Primate Rescue Center, which can be visited with staff accompaniment, focuses its rescue efforts on channels of illegal trade, then tries to establish populations in captivity. Although Cuc Phuong's habitat would seem to be the perfect place to see Vietnam's wildlife in full splendor, mammal- and bird-watching are sadly not particularly successful pastimes in the park. Despite Cuc Phuong's status as a protected preserve, the primary forest habitat has been heavily denuded during the past few decades, and officials believe the park's wildlife numbers are dwindling due to increased hunting and high tourism pressures, which have led to the creation of in-park facilities, hiking trails, and paved roads.

Despite the misfortunes of northern Vietnam's animals, Cuc Phuong is quite beautiful. In April, it's particularly lovely with swarms of butterflies. Dozens of miles of trails lead to such highlights as cascading Giao Thuy waterfall, a 1,000-year-old tree, and Con Moong Cave—the "cave of early man"—where evidence of prehistoric humans has been discovered. Longer hikes lead to some Muong villages. Many trails are well marked, but exploring this thick forest would be foolish without a guide. Be sure to bring lots of mosquito repellent, especially if you plan to stay the night.