Howard Limbert, the Briton who became the first westerner to explore the world's largest cave, Son Doong, in Vietnam three years ago, fell in love with caves at 15.
British excavator Howard Limbert (middle) with his wife Debbie Limbert and Ho Khanh, a local guide, during their exploration at a cave in Phong Nha-Ke Bang national park in central Vienam.
"The feeling of being the first one to step on a totally untouched place is hard to describe," he told Tuoi Tre.
The 54-year-old's interest in caves was sparked off during his first visit to a cave in Yorkshire in northern Britain, where a teacher left him and his classmates to explore.
He then joined a caving club and made his own discoveries while also studying to be a doctor.
In 1989, after having discovered thousands of caves around the world, he turned his focus to Asia whose caves remained a mystery to western science.
He sought support in Laos, Myanmar, and Vietnam but received a yes only from the Hanoi University of Natural Sciences, which provided the contacts and instructions he needed to embark on the first of many visits to Phong Nha-Ke Bang National Park in 1990.
His team had to stay in the only concrete house in Son Trach Commune. He and his wife, also a doctor, brought medicines and taught locals how to treat malaria and protect themselves from it.
Limbert says he came to Vietnam just to climb, crawl, and dive into caves to satisfy his desire. He also planned to map the park.
But he has done much more than that by establishing Son Doong as the largest cave in the world.
The UK's BBC, Japanese channel NHK, and the US's National Geographic have all made documentaries about the cave.
Debbie Limbert, his wife, says the media agencies became interested in caves after Oscar-winning American director James Cameron last year produced "Sanctum," a 3D movie featuring an underwater cave diving team.
The agencies sent filmmakers to Son Doong and Limbert became their guide, she says.
But even before Son Doong, in 2003 his team won UNESCO world heritage recognition for Phong Nha Ke Bang by many discoveries including Khe Ry, the world's longest cave with a stream.
"I want to promote the beauty and distinctiveness of Vietnamese caves to the world," Limbert says.
"I want to do something to bring more tourists to Quang Binh, so that locals have a better life."
He thanked local governments for giving him excavation permits and local people for being his guides.
The commune has changed out of sight since his first visit there, with tourism revenues more than doubling last year from 2009 to VND24.5 billion (US$1.2 million) and more than 3,400 jobs being created.
But it will be a lot longer before Limbert is done with the park.
The area is so vast that he has only explored 10 percent of it in the past 22 years, while it only took him a few years to step into 90 percent of caves in the UK, he says.
His team has discovered hundreds of caves at the park and mapped a 300-kilometer area.
"I believe that marvelous caves, even larger than Son Doong, will be discovered."
He says he is "extremely lucky" that his wife shares his caving interest since he will always have someone to take care of him and no one at home worrying about him.
Young Vietnamese should turn off their TVs and put on their backpacks to start discovering their country, he says.
"Your country is very beautiful, and a television and couch will not really let you understand that beauty."
He, his wife, and nine other members of the British Cave Research Association have been in Vietnam since last month, his 15th visit to the country, exploring 20 new caves in Phong Nha Ke Bang.