|
 |


 |
 |
 |
 |
 |
 |
Tubular trail |
 |
 |
 |
 |
|
 |
 |
 |
| Robert Holmes/CORBIS |
A tunnel leading into an enchanted forest? The Thurston Lava Tube in Volcanoes National Park seems just that. Lush tree ferns cloaking the tube's entrance starkly contrast with the desolate crater landscape just a few miles away. The 500-foot tube was formed when the outer layer cooled and hardened, and the molten lava inside flowed out.
|
|
 |
 |
 |
 |
|
 |
 |
 |
 |
 |
 |
 |
 |
|