ナショナルジオグラフィックさんのインスタグラム写真 - (ナショナルジオグラフィックInstagram)「Photo by Stephen Alvarez @salvarezphoto / The Rumble Room is a five-acre underground expanse discovered deep in a cave on the Cumberland Plateau in Tennessee. The only way into the cave is via a long, low, wet crawl and a 200-foot rappel into the room. Beyond this room are miles and miles of huge passages unknown until cave explorer Marion O. Smith discovered the cave in the late 1990s. I have always been fascinated by original physical exploration. The act of actually going somewhere that no one has been before is a privilege that few have ever had. Usually we associate the act with the deep ocean or outer space. However, a small group of dedicated cave explorers discovered, explored, and mapped Rumbling Falls cave practically in their own backyard. For more images from around the world and close to home check out @salvarezphoto.」12月30日 4時41分