Sinkholes

Friend, Sandra: - Climbing through caverns, sliding into sinkholes, and clambering up volcanoes is all in a day's work for Sandra Friend, who regularly goes out in the field while researching her articles and books. She has written more than 200 articles on travel, outdoors, and geological topics and is the author of children's earth science books, Exploring Planet Earth. Sinkholes took more than 5 years of research. She lives in Orlando, Florida.