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 Robbie Shone @shonephoto Lechuguilla Cave, in Carlsbad Caverns National Park, offers many wondrous sights. We illuminated this stalagmite from the outside, giving it a warm, orange glow. What is most unusual about this stalagmite is the hole in the middle. It's very rare and is probably formed when a drop of more acidic water falls from the ceiling and erodes the inside of the stalagmite.」8月30日 12時59分