For the last 3 days and 2 nights I have been trekking through dense Vietnamese jungle mountains led only by a local guide with a machete. The trail—only legally traversed by 500 people a year—was barely visible through the thick, wet foliage. Our group of 8 scaled 30 km of mountainous jungle slippery with ankle-deep mud as our guide chopped away at the overgrowth. On the third day—after 2 nights of sleeping among the trees and bathing in the river—we arrived at what lies behind me: Son Doong Cave. The largest cave in the world, it’s enormity is impossible to capture in a photo. The cave is so massive you could fly a 787 through it and it possesses its own climatic system. We descended 2 km into the earth and scaled the rocky, pitch-black underground with only our headlamps for light. Stalactites and stalagmites 100 feet high towered around us. Massive hand-sized spiders and bats scuttled the walls. We squeezed between small rocky passages to emerge into massive chambers with ceilings that glittered with silica. The air was humid and cold, rich with the smell of minerals. Only the drip drip drip of water chipping away at the limestone for millennia could be heard. This is nature’s cathedral. And I worship.