A funny thing happens when you take a portrait photo in Papua New Guinea: your subject will always frown. Perhaps they’re hiding their cherry-red teeth – stained by betel nut chewing – or maybe it’s the cultural norm to make a serious face when photographed. Either way, when locals don’t feel the pressure of a pointed lens they flash the most genuine smiles on the planet.

These smiles shine especially bright during the country’s annual Sing Sings and festivals – gatherings of faraway tribes who come together to share the traditions that make them culturally unique. With over 800 languages spoken in PNG, a warm, grinning face is the de facto nationwide currency of kindness and hospitality.

Travel expert Brandon Presser is an award-winning writer, photographer and TV personality. He's penned over 40 guidebooks—most for Lonely Planet—and has appeared on a variety of programs for ABC, CBS and the Weather Channel. For more, check out www.brandonpresser.com.