7. Hana Highway, Hawaii, USA
Hana Highway on the island of Maui is one of the most scenic roads in the world, but it’s also one of the most challenging. The road spans 64.4 miles and features 620 curves and 59 bridges, many of which are one lane. Drivers are constantly twisting and turning through dense rainforests, crossing narrow bridges, and navigating steep drop-offs. The road is often wet from rainfall, adding to the danger of slipping. The reward for brave drivers, however, is the stunning tropical scenery, including waterfalls, lush greenery, and breathtaking coastal views.