A major community in the Metropolitan City of Turin, Ivrea is a 30.19 square kilometer (11.65 square miles) expanse of picturesque groves, majestic castles, ancient arched bridges and pristine wetlands. It can be found along the route to the beautiful Aosta Valley and has been known to have been inhabited since the Neolithic period. Written records suggest that the Celts had established a thriving settlement here during the 5th-century BCE. In addition to the Celts, Ivrea has been most-notably ruled by the Roman Empire, Lombards, Franks, and the Savoys. Known around the world for its historic sights, it was declared as a UNESCO World Heritage Site in 2018. Ivrea's most popular sights include the Castle of Ivrea, the Capitular Library, the Church of San Gaudenzio and Cappella dei Tre Re.