Expedition

That's our first glimpse of the limestone mountains we're heading into. (dramatic music) We're in the Indonesian part of Borneo. Here vast, jagged mountains burst out of dense pristine forest. Borneo's been a really special place to me for expeditions. My very first expeditions were here nearly 30 years ago now, which makes me feel very old. But more than that, in these mountains are the memories of our ancestors. (tranquil music) We're going up river to meet an Indonesian team of experts. Less than a year ago, they discovered that ancient cave art in these mountains is amongst the oldest on the planet. This could be one of the most significant places on Earth for the study of human history. But it could also be the most challenging. At the far end of this formidable mountain range, there are rumored to be unmapped caves. We want to be the first team to track them down and discover whether they're hiding priceless artifacts. Because of what's been found here and what that's led us to know, to understand, about our own history, there's a move to try and turn them into a UNESCO World Heritage Site, a reserve, to make it a protected place. It's incredibly important because deforestation is coming in from all sides, so trying to find some degree of protection is incredibly important, and it has to happen soon. The loggers, chainsaws, and trucks are poised to move in, but if we can find new archeological treasures here, we could help protect this remote corner of Borneo forever.