Zedekiah's Cave – also known as Solomon's Quarries – is a five-acre underground meleke limestone quarry that runs the length of five city blocks under the Muslim Quarter of the Old City of Jerusalem. It was carved over a period of several thousand years and is a remnant of the biggest quarry in Jerusalem, having once stretched all the way from Jeremiah's Grotto and the Garden Tomb – a traditional Protestant site of Jesus's burial – to the walls of the Old City. (Wiki)