When her husband passed away eighteen years ago, Mary Lou Mahaney, then 72, found herself with a lot of alone time on her hands. She always wanted to travel, but her husband was never into the idea, and so the couple, for the duration of their married life, they didn't travel much. "But after his passing," Mahaney, a retiree from Silver Spring, MD, says, "I decided that I had to see the world." And see the world she did. With a vengeance. Today, at 90, Mahaney has visited every continent and over 100 countries. She also had some amazing adventures...