Lara Logan tours The Explorers Club

Flags awarded by the legendary Explorers Club have been carried on expeditions to remote places including the moon and the deep sea. In this 60 Minutes Overtime story (posted in the video player above), explorer Bob Ballard gives Lara Logan a tour of the club's artifacts, including the flag for which he's famous: the one aboard the discovery expedition that found the Titanic.

With over 50 percent of the U.S. lying underwater, Ballard believes that huge discoveries await. Ballard has close to 150 expeditions under his belt but shows no signs of stopping. He's committed the rest of his life to searching America's seas. Lara Logan's report this week, "The Unknown America," goes aboard the Nautilus, a 200-foot state-of-the-art ship, to get a peek at what's out there.

"These are my heroes-- as a child. These were the books I read. The books of great explorers and adventurers and never thinking that I would someday...be on the wall."

At The Explorers Club in New York City, Ballard's portrait hangs alongside his childhood heroes, something that Ballard tells Logan he never imagined.

"These are my heroes-- as a child. These were the books I read. The books of great explorers and adventurers and never thinking that I would someday...be on the wall."

Editor's Note: This segment was produced by Sarah Shafer and Evie Salomon. It was originally published on May 10, 2015