According to the United Nations, we probably throw away over one billion tonne of waste every year. Some goes into landfill, some is destroyed and some is recycled. The mountain of cast-off litter is not just a huge environmental challenge, but a logistical one as well. Bridget Kendall explores ideas about how to harness waste with - Martin Medina, a global waste consultant, who suggests scavenging might be the answer to developing country’s growing waste problems; Dr Tom Licence, an historian at the University of East Anglia and ‘garbologist’, who uses archaeological beachcombing for historical rubbish to unveil our detailed past; Polly Morgan an artist who uses taxidermy to ascribe new meaning to what was once discarded and dead. (Photo: A rubbish tip in Kolonawa suburb of Colombo, Sri Lanka. Credit: Getty Images)