Mount Gower — New South Wales, Australia

Not to be confused with California’s Mount Gower, Australia’s version is the highest peak on Lord Howe Island, a tiny speck of paradise floating in a placid sea about 400 miles northeast of Sydney. Though anyone can visit the island — remarkably clear water and an abundance of sea life draw divers and snorkelers from all over the world — hikers who want to take the eight-mile trek to reach the 2,870-foot summit must hire a guide. It makes sense: the hike is not just remarkably strenuous, but takes place on an unmarked trail that’s notoriously difficult to navigate and starts with a dizzying stretch of pathway that snakes along a narrow precipice far above the ocean. From there, the trail is loaded with rope-assisted climbs, sheer drops, and mossy rocks. However, the sights as you wind your way to the top — including a turquoise lagoon, a rare orchid-filled cloud forest, an extinct volcano, and miles of uninterrupted ocean — make the hike worth every sweaty step. 

Full day tours cost around $130 per person.