QUANG BINH — Tu Lan Cave, sister of the biggest cave in the world, Son Doong, is offering visitors treks, swimming, caving trips and a race.

The race will raise funds to build floating houses that protect locals in nearby Tan Hoa Commune from floods.

According to Nguyen Chau A, director of a local company running tour programmes to Tu Lan and Son Doong grottos, this year’s Tu Lan Race will accommodate 100 visitors, both foreigners and locals, in 10 teams.

A said the race includes 10km boating upwards the stream of Rao Nan, a local river, a 17km run across sweet corn fields in the commune, trekking in the jungle and swimming in an underground stream inside the cave.

The race will take place from March 31 to April 3 around and in Tu Lan cave system, which is similar to Son Doong, though smaller.

This year’s race features one team from the Nguoi Bat Tu (The Immortal) movie crew. Vietnamese-American director Victor Vu’s movie was largely filmed in the caves of Tu Lan and Phong Nha, and nearby scenic landscapes.

The winning team will be awarded VND150 million (US$6,700).

A said the race will help raise funds to build five floating houses and a library in the commune with a total cost of VND210 million ($9,400).

The commune is in a low-lying region, surrounded by mountains and several streams, making it vulnerable floodwater during monsoons. The houses are in ordinary structures but with large buoys underneath and a rope to hold them still from rising floodwaters.

The races held annually since 2015 have helped build 40 floating houses, but more are needed, according to A. — VNS