The Hardy Boys series, first published in 1927, has sold more than 70 million copies! Now with a brand-new look, this is an edition that collectors won't want to miss! In The Secret of the Caves, the seventh book in the incredibly popular, long-running series, Frank and Joe Hardy discover the secret of the Honeycomb Caves while searching for a missing professor. A special treat for Hardy Boys fans and any reader who's new to the series!

Recounts the true story of how four boys looking for buried treasure in the south of France in 1940 stumbled upon something much more valuable--a sealed cave whose walls were covered with prehistoric paintings and engravings.

What's more dangerous than scaling Mount Everest? For mountaineer Pete Athans, the answer lies in the ancient kingdom of Mustang, a remote part of the Asian nation of Nepal. Long-abandoned caves built high into steep cliffs contain amazing treasures—and pose incredible dangers. Reaching these "sky caves" safely takes guts, smarts, and luck. And then there's the question of what to do with a two-thousand-year-old human skull. . . From 2007 to 2012, Pete explored Mustang's sky caves with a team that included scientists, mountain climbers, and even two children. They found mummies, murals, manuscripts, and other priceless artifacts. Follow Pete on his dangerous trips to the sky caves and discover the secrets the caves revealed.

When Hildy finds a stolen watch concealing a crude, hand-drawn map, she is accused of the theft and must try to clear her name.

DISCOVER JUST HOW LONG IT REALLY TAKES FOR A CAVE TO FORM