The Atlantic coastline of County Mayo is full of dramatic features, but Dún na mBó is something not to be missed. Found on the Belmullet Peninsula just south of Erris Head, this remarkable place features a winning confluence of nature and public art: a natural blowhole accentuated by an evocative sculpture that doubles as a means of keeping spectators safe from tumbling into the hole. The blowhole at Dún na mBó (also known as Doonamo Point) is located near the site of an ancient promontory fort that likely dates to the…