River at the Centre of the Earth

Marco digs and squeezes through dark Italian caves hundreds of metres underground. He is continuing an amateur 200 year search for the mysterious river Reka. Death lies at every corner - falling stalactites, CO2 poisoning. It's a tale of generations fixated with one deep hole in their backyard. The old cavers never found the Reka, and today they hand over to new enthusiasts to continue the quest.