I read this book when I was in middle school in the mid-90s. This student (at a boarding school?) is blindfolded by another student and led through the woods following a windy path so he won’t be able to retrace his steps later. They reach a secret cave or something where the other student has discovered ancient ruins of tiny buildings (like maybe pygmies lived there, or some unknown tiny people?). Together, over a long period of time, they excavate these buildings. Then for some reason, (maybe this knowledge is going to get into the wrong hands?) the main character decides he needs to get back to the site on his own. He’s never seen the way, since he’s always blindfolded, but he remembers the twists and turns by feel. Once he arrives there, he destroys the buildings he worked so hard to uncover so no one will ever know they were there.
Thanks!