After becoming a world-recognized neurosurgeon at Mayo Clinic, Dr. Kendall Lee wants to do more. So he joined the U.S. Navy to give back to his country. At 21 years old, Dr. Lee became an American citizen. He was born in South Korea and moved to the United States when he was just 10 years old... He said he is thankful for everything this country has given him. So he signed up for the U.S. Navy. "I wanted to serve the country that I believe in, I think this country has given me so much," said Dr. Lee.