Pakistan, April 4 -- A 24-year-old American tourist, Mykhailo Polyakov, was arrested in India for illegally landing on North Sentinel Island. He arrived in Port Blair on March 26 and planned his visit secretly. Authorities say he crossed the sea in a modified inflatable boat, leaving offerings of Diet Coke and a coconut for the isolated Sentinelese tribe.

The Sentinelese are one of the most isolated tribes in the world. They have lived on North Sentinel Island for over 50,000 years without significant outside contact. As hunter-gatherers, they use bows, arrows, and spears to survive. Their population is estimated between 50 and 150, but the Indian government respects their isolation and does not conduct a census.

Since 1956, North Senti...