Phong Nha-Kẻ Bàng:
Phong Nha-Kẻ Bàng (Vietnamese: Vườn quốc gia Phong Nha-Kẻ Bàng) is a national park and UNESCO World Heritage Site in the Bố Trạch and Minh Hóa districts of central Quảng Bình Province in the North Central Coast region, about 500 km south of Hanoi.

There are many caves in this limestone mountain area with stalagmites and stalactites, as well as underground rivers and waterfalls. Tu Lan Cave System comprises over 10 caves, some of which were originally discovered and explored in 1992, and some of which were just found in the past couple years. Hang Ton, first found in 1992 and explored more in depth in 2012, appears first on the horizon on a trek to this intricate cave system.



Paradise Cave:
Thiên Đường Cave (Paradise Cave: Thiên Đường Cave(Paradise Cave)is a cave in Phong Nha-Kẻ Bàng National Park, UNESCO's World Heritage Site, 60 km northwest of Đồng Hới city. Thiên Đường Cave is located on an elevation of 200 meters above the sea level, near the west branch of Ho Chi Minh Highway, in Son Trach Commune, Bố Trạch District, Quảng Bình Province, Vietnam.

The cave was discovered by a local man in 2005 and the first 5 km of this cave was explored by explorers from British Cave Research Association in 2005, the whole 31 km was explored and publicly announced by the British cave explorers.

This cave is 31 km long, longer than Phong Nha Cave which had been considered the longest cave in this national park. The height can reach to 72 m and 150 m wide. The limestone formation is also more spectacular than that of Phong Nha Cave. The British cave explorers were impressed by the beautiful and spectacular stalactites and stalagmites inside this cave and they named it Thiên Đường Cave (Paradise Cave). In 2012, a new scorpion species Vietbocap thienduongensis was found here.

Tu Lan Cave,Ken Cave Ton Cave...
Because the tectonic plates in this region are always moving and bumping into each other, the mountains are still rising and moving up. The rivers continue to cut into the bottom of the mountain, carving new caves over time. Hence, the river caves that are at a lower elevation are much younger than the higher, dry caves as they were more recently created. The river caves in this system such as Ken Cave and Tu Lan Cave are very young, only about 3 million years old.

The higher, dry caves (dry Tu Lan and Ton Cave) are much older, and date around 5 million years old. The French scientist Pierre G commented: Tu Lan Cave System have the largest, deepest, longest, highest with many of connecting caves including inactive dry caves & active wet caves; including a number of natural phenomena such as the deepest Karst Doline of Southeast Asia (with a depth of more than 255m) and the habitat, stunning natural wonders, the majestic, unique of tropical jungle on the 400 million years of limestone."

The stalactites and stalagmites are enormous . One of the caves in the Tu Lan cave system, Ken Cave, even had its formations featured recently in National Geographic by world renowned photographer Carsten Peter.
 

National parks

This cycling trip will take you from Hoi An to Phong Nha national park. Ride the highest peak in the central, explore the the UNESCO-listed Hue citadel, the historic DMZ and Vinh Moc tunnels before heading to Phong Nha where the famous KONG'S movie was filmed in Viet Nam.