The caves are over 10 kilometers in length when put together.

Nhan Danreports that caving experts from the British Royal Caves Association (BCRA) discovered 12 previously undescribed caverns during an expedition earlier in the year in Bo Trach, Quang Ninh and Minh Hoa districts in Quang Binh. 

Three caves were found in Bo Trach, namely Doc Co (555 meters in length), End Cave (51.5 meters long) and Dry Vom (413 meters).

The four new caves discovered in Quang Ninh District include Nuoc Ngam (3,872 meters long), Nuoc Lan (1,919 meters), Hung Thoai (460 meters) and Coincidental Cave (413 meters).

The remaining five are in Minh Hoa: Three Horned Viper (195 meters), Phu Nhieu (2,012 meters), Cha Ra (314 meters), Thoang Lip (137 meters) and Ma Lon (463 meters).

According to Howard Limbert, a member of the 11-person exploration team, the British experts had to undergo 14 days of quarantine as one of them was on the same UK–Vietnam flight with a Covid-19 patient. They all tested negative for the virus and flew back home on March 21, reports Vietnam Times.

VietnamNetadds that 11 BCRA experts surveyed the region from March 3 to 20, and found no traces of human exploration in the 12 above caves.

Phong Nha-Ke Bang National Park, which these caves are part of, is already considered Vietnam's "cave capital," and is home to the world's largest known such feature, Son Doong.

[Photo via Flickr user undeklinable]