Robert Hanna, great-great-grandson of John Muir, will give a presentation May 19 from 7-9pm at Unity at the Lake, 1195 Rufus Allen Blvd., South Lake Tahoe.

Lake of the Sky Outfitters and Range of Light are sponsoring the event.

Free tickets are available at Lake of the Sky Outfitters at the Y in South Lake Tahoe. A ticket is required for entry.