The soft, spongey mud mutes our footsteps. Our arms, slick with sunblock, DEET and sweat from the heavy, humid air, leave greasy stains on our T-shirts as we tramp through the jungle in our hiking boots. Our guide, who is wearing flip flops and easily outdistances us on the rocky, slippery and muddy paths, leads the way. When we pause for a sip of water and ask him how much further it is to the cave, he waves his hand and says: “One kilometre”. He smiles…