Eureka Moment : An Indian anthropologist Dr Madhumala Chattopadhyay , perhaps first and hopefully the last, human being from "modern world" landed in Sentinel island in 1991 and interacted with Sentinelese. Sentineles allowed Indian team  to come ashore and took gifts.

Dr Chattopadhya narrates encounter in book-

Travelers' Tales India

edited by James O'Reilly, Larry Habegge