Michelangelo's David is actually made up of debris.

The priceless statue was carved out of the left over remains of millions and millions of shellfish. These shellfish lived in the shallow tropical waters which covered much of Europe during the Jurassic period (199.6 to 145.5 million years ago). Over millions of years this sedimentary debris grew deeper and harder forming calcium carbonate (CaCO3) or limestone. Later huge tectonic forces, or movements in the earth's plates further compressed the calcium carbonate and through metamorphosis recrystallized the debris. This helped form marble.

Michelangelo's David is made from marble found in the Massa Carrara region in Tuscany, Italy.

Carrara marble is considered to be the world's most valuable marble and has been mined since 9th century BC.

The ancient and continued use of the region for mining has meant that whole sides of mountains have been carved away. Indeed licenses to carve out mountain sides have been passed through generations of families for hundreds of years.