Phong Nha National Park

Paradise Cave - Zipline - Dark Cave - Kayaking (full day tour).
 
Thien Duong or Paradise Cave, opened in 2010, is 31 kilometers long, making it the longest dry cave in Asia. Walking inside is as sublime, heavenly and humbling at the same time as visiting a grand cathedral. With vaulted ceilings rich in stalactites, it is an exceptionally beautiful cave.
In 2005, a local looking for bamboo heard a howling wind that was supposed to be coming from the mountain - and the rest is history. The British Caving Association began exploring Paradise Cave, and after four years of research, it proved to be an astonishing 31 kilometers long, taking Phong Nha's record title as the longest cave in Phong Nha-Ke Bang National Park.
Hang Toi, better known as Dark Cave, has been adapted to meet the demands for adventurers. With artificial bells and whistles, such as the longest zip line in Vietnam, you slide into the cave with a safety harness and courage, along the high walls, into a dark, narrow cavern full of dense, wonderfully slippery mud. "Dark" refers to the unlit cave itself or your body after the mud bath. Either way, be prepared to get really dirty with a high fun factor.

At 8am, our tour guide will pick you up at your hotel in Dong Hoi town.
9.30, Visit Paradise Cave, about 1.5 - 2 hours.
11.30, Lunch at local restaurant
13.00, visit Dark Cave, zip-line / kayak, mud bath.
16.00 - 17.00, return to Dong Hoi.