Exploring Underwater Caves

Diver and photographer Jill Heinerth talks about some of her most dangerous and exhilarating experiences underwater — like getting trapped inside an iceberg in Antarctica. Heinerth also shares how she stays calm when things go wrong: "I take a really deep breath and try and slow my heart, slow my breathing, and then just focus on pragmatic small steps," she says. Her new book is 'Into the Planet.'

Also, book critic Maureen Corrigan reviews two mystery novels — Laura Lippman's 'Lady in the Lake' and Ruth Ware's 'The Turn of the Key.'