Son Doong Cave in Vietnam's central province of Quang Binh (Photo: Getty Images)

International air links with many Asian cities provide easy access to attractions like the Golden Bridge at nearby Ba Na Hills in Da Nang city.

"Exploring the caves and rugged river and jungle wilderness of Phong Nha-Ke Bang National Park is essential for adventurous and intrepid travellers," Lonely Planet said.

Hue city’s vibrant cuisine showcases the city's imperial legacy, while in Hoi An’s storied laneways, local dishes include fragrant Cao Lau noodles.

Seafood stars in nearby Da Nang city, located along the Han River, which is becoming one of Vietnam's most exciting urban destinations, the travel magazine said.

The former imperial capital of Hue, which once witnessed the glories and collapse of the Nguyen Dynasty (1802-1945), and the last royals to rule the country, is famous as a food paradise.

The caves, including the world’s largest, a rugged river, and the jungle wilderness of the Phong Nha-Ke Bang National Park in Quang Binh province beckon the adventurous.

The Phong Nha-Ke Bang National Park is referred to as the Kingdom of Caves. The 900-sq-km park, which UNESCO recognised as a global heritage site in 2003, has over 300 of them formed about 400 million years ago.