Mae tirwedd lechi gogledd-orllewin Cymru wedi'i hychwanegu at Restr Safleoedd Treftadaeth y Byd UNESCO, sy'n golygu mai dyma’r pedwerydd Safle Treftadaeth y Byd yng Nghymru.
The slate landscape of north-west Wales has been added to the UNESCO World Heritage List, making it the fourth World Heritage Site in Wales.