The 20 most beautiful islands in the world.

MUST SWIM in the Blue Lagoon, Iceland's famed geothermal pool, surreally set among black lava fields just outside Grindavik.

MUST WATCH the greatest puffin show on earth in August on the island of Heimaey in southern Iceland's Westman Islands.

MUST TEE OFF at midnight -- in broad daylight -- at the Akureyri Golf Club, just 40 miles south of the Arctic Circle.

MUST STAY at Hotel Budir, a refined and isolated getaway on Iceland's majestic Snaefellsnes Peninsula surrounded by glaciers and lava fields.

MUST TASTE the arctic trout at Reykjavik's new Vox restaurant in the Nordica Hotel.