The rocky south-west coast of Sardinia combines natural beauty and impressive industrial heritage. The Miniera di Masua and Porto Flavia are within the Geological Mining Park of Sardinia. Mining at Masua dates to the seventeenth century. It expanded with the Montesanto company in 1863, producing lead and zinc with 700 workers. In 1922 it was taken over by the Belgian company Sociétè de la Vieille Montagne, which invested in a major project for loading ore into ships. The engineer Cesare Vecelli designed a pair of tunnels through the cliffs to where ships could wait safely. The top tunnel 600 metres long took ore by electric railway to nine silos 18 metres deep, which stored 10,000 tons ready for loading ships. A conveyer in the bottom tunnel 100 metres long carried it from the silos out over the waiting ships. Vecelli named the port for his daughter Flavia. Visitors to the tunnels go by pre-booked guided tours, which take them through the tunnels to a tall archway and a tower built into the cliff. The mining village and a museum of mining machinery can be seen at Masua.