The twelfth week of the 2021 winter-spring session of Lifetime Learning brings back Mark McGrath for another virtual walking tour, this time through sites of historical significance on Cape Cod. Also in the line-up: a new course on horseshoe crabs led by Audubon naturalist Mark Faherty, as well as continuing courses in music and medical science.

On Tuesday, April 20 from 1:30 to 3 p.m., McGrath presents “Cape Cod Walks to History.” Participants will take walks, virtually, to places of Cape Cod history, recall the works of Thoreau, Hopper and Oliver and uncover many little-known gems of the past.

On Wednesday, April 21 from 1:30 to 3 p.m., Joseph Marchio, assistant conductor of the Cape Symphony, presents the third class in a four-part series on “American’s Musical Trailblazers: Charles Ives and Aaron Copland.” Explore how both composers gave America its own musical voice by incorporating folk, jazz, and American sacred musical elements.

On Friday morning, April 23 from 10:30 a.m. to noon, Stephen Munroe continues his course on “The Molecular Revolution in Biology and Medicine.” This fourth class in the five-part-series will focus on viruses, cancer, and the immune system.

And on Friday afternoon, from 1:30 to 3, Mark Faherty, science coordinator at Mass. Audubon’s Wellfleet Bay Wildlife Sanctuary, presents “Horseshoe Crabs Explored.” This is part one of a two-class Mass. Audubon program. Mark will discuss the Wellfleet Bay Wildlife Sanctuary’s horseshoe crab research program and describe horseshoe crab biology, behavior, conservation, monitoring and tagging. The second class will be on April 30 with Ian Ives presenting his course on “The Incredible Edible Oyster.”

Course information, registration, and a PDF of the brochure are available at www.friendsofsnowlibrary.org/lifetime-learning-program. Brochures and registration forms are also available at Snow Library. Register online, at the library (drop your registration in the drop box), or by mail. Registration is ongoing. Please register at least 48 hours prior to any class. There is a suggested donation of $10 per course.