You can explore these enormous passageways left behind by rushing rivers of molten lava in caves around the world.

I posted this shot simply because I'm in awe of my new camera's low light capability. There was NO light inside this lava tube besides the dim incandescents you see. This was shot handheld at ISO 3200. It's noisy, but still gave me a useable image.

Underground tunnels created by lava flows provided humans with shelter for thousands of years beneath the hot desert landscape of Saudi Arabia

The Kamchatka Peninsula is a 1,250-kilometre-long (780 mi) peninsula in the Russian Far East, with an area of about 270,000 km2 (100,000 sq mi). It lies between the Pacific Ocean to the east and the Sea of Okhotsk to the west.

Scientists have long wondered how we might live in other atmospheres. On Mars, at least, the answer could be a network of large underground lava tubes.

Nāhuku, or Thurston Lava Tube, in Hawaiʻi Volcanoes National Park has reopened for the second time in two years after shutdowns due to natural disasters.