Minerals become dissolved in the water as it moves through the underground rocks.

In the late 1960s, the format switched to underground rock, playing primarily album cuts.

They became "the reigning kings of American underground rock, for a few years".

It plays host to is own internet radio station that specialises in playing local underground rock and punk music.

Learn how we can get more of this valuable fuel from underground rocks.

Most beautiful was the 41-year-old underground rock legend's smile, which blossomed even more gloriously than the music.

Geothermal power plants use steam extracted from hot underground rocks.

Joy is known for his work in several underground rock and post-hardcore bands.

The major source of the heat is molten underground rock, or magma.

The underground rock was as hard and durable as granite.