The longest road in the world, according to Guinness World Records, is the Pan-American Highway, which runs 19,000 miles through fourteen countries and connects to four more between North America and South America.
Carretera a los Yungas (Bolivia)Locally known as the 'route of death', this Bolivian road is 80 km long and considered by many as the world's most dangerous road.
Hardknott Pass is considered to be one of the most challenging in the UK. It has earned this consideration due to its series of hairpin bends and the high risk of ice on the road. It is a steep, twisting, single-track road that cuts right through the heart of the Lake District between the Duddon Valley and Eskdale.