Mountainous and luminously green, the Virgin Islands number about 100, some governed by the United States and others by Great Britain. The larger islands appear as mossy green hills rising dramatically out of turquoise seas; others are little more than rocky outcroppings rimmed by whispery white-sand beaches waiting for Robinson Crusoe to call. The former haunt of derring-do sea captains and pirate marauders, today many of the Virgin Islands are invaded by thousands of visitors, arriving by plane and cruise ship, suntan lotion in hand.