A lava tube formed when molten lava flowed out of the ground. As the surface cooled, it formed a crust that was left behind as a tube when the lava eventually finished flowing out. Craters of the Moon National Monument, Idaho.
This is great Miriam, did you actually climb down in there to get this shot. Nice clarity and well balance.The beautiful sky also makes this a splendid addition to your gallery. Thanks for sharing this with us, 10/10 and saved in my favs!