Chewing moma is a custom of the Ifugao people, as old and alive today as the rice terraces they cultivate. More than 2,000 years ago, they arrived on the island of Luzon in the Philippines, and headed north into the Cordillera Mountains. They tamed this vertical world of 3,000ft peaks, transforming forested slopes into irrigated steps to create the immense green amphitheatres of rice paddies that form the lifeblood of their villages, known as 'barangays'. But there is no rice farming today. When the planting season is over, the terraces are left to rest and barangays across the Ifugao kingdom have gathered in Hungduan for the annual cultural festival.