Emerald Bay, Lake Tahoe, California.

You need to hike down from the nearby road, CA Route 89, to get to this beach, in a tucked-away inlet off of the massive Lake Tahoe on the Nevada-California border. BI's Associate News Editor Kieran Corcoran said: "There's a Viking-style house built by a weird rich American called Vikingsholm, and an island in the lake with a stone ruin on. The beach has clear water and incredible scenery."