This year’s National Park Week, from April 20 to 28, centered on Earth Day, will offer free weekday admission to all 398 national parks from April 22 to 26, adding 134 more historic sites, preserves, recreation areas and other sites to the usual 264 with no entrance fee. Earth Day’s 43rd anniversary celebrations throughout America and worldwide will encourage everyone to join in the next “billion acts of green,” aligned with the theme: The Face of Climate Change.

“In the face of unprecedented occurrences of extreme weather, loss of species and pollution, it is clear that climate change is affecting our planet. We cannot afford to wait any longer to act,” advises the Earth Day Network, which posts many ideas for participating at EarthDay.org/takeaction.

Find local park activities by state at nps.gov/findapark/event-search.htm or check a park’s website for upcoming programs. Following are other leading local events that will help citizens of all ages answer the call to go green.

SATURDAY, APRIL 13

River Ceremony Workshops – Apr 13 & 21. 1-4pm. Led by artist and certified InterPlay trainer CC King. Workshops will explore the many ways one can construct a floating sculpture out of natural branch and grass fibers. Sculptures will be launched during the Earth Day River Ceremony (Apr 27). To register: 978-371-0820 x 213. EmersonUmbrella.org.

SUNDAY, APRIL 14

“Muskie Moves” Workshop – With CC King. Explore movement inspired by local “edges”, whether they are natural habitats and creatures or one’s personal edges, within and without. Participants encouraged to reveal some of their own moves and breathe life into Earth Day celebration creations: puppets, banners, songs and or stories for both public and private enjoyment. To register: 978- 371-0820 x 213. EmersonUmbrella.org.

WEDNESDAY, APRIL 17

Earth Week: On the Move – Apr 17-22. 10am-4pm. Float, fly and roll your way through fun experiences at the Ecotarium as you learn how things move across air, land, and water. Join in an Earth Day Festival celebration April 20 when admission is half price. $14/ adults, $8/18 & under, free/children under 2. EcoTarium, 222 Harrington Way, Worcester. 508-929-2701. EcoTarium.org.

SATURDAY, APRIL 20

14th Annual Charles River Cleanup – 9am-12pm. Join thousands of others along 80 miles of the Charles River for an Earth Day cleanup. Volunteers pick up trash along the shorelines making the river cleaner, healthier and more beautiful. Free. Charles River, Boston. CRWA.org.

Earth Day/Arbor Day Celebration – 10am. Come for a day of timely demonstrations and information sharing, children’s nature games and crafts. Representatives from various local conservation groups will offer sustainable solutions for a green planet. Demonstra- tions and guided tours throughout the day. Free. Mass Audubon’s Stony Brook Wildlife Sanctuary, 108 North St, Norfolk. 508-528-3140. MassAudubon.org.

Earth Day Family Wetlands Exploration – 1pm. Each spring frogs, salamanders and many other creatures are hatched in wetlands. Some will live in the pond, others race against weather to develop before the wetlands dry up. Explore both of these worlds on Earth Day. Adult: $5/member, $6/nonmember; Child: $3/member, $4/nonmember. Mass Audubon’s Wildwood Camp, 462 Old New Ipswich Rd, Rindge, NH. 866-627-2267.  MassAudubon.org.

SUNDAY, APRIL 21

Party for the Planet at Franklin Park Zoo – 10am-3pm. Make friends with the animals during a day of events that will include performances by the Green Rockers and POP Alert. Throughout the day, observe as zookeepers feed ice treats to the lions, tigers and gorillas as well as the mandrills, keas and more. $16/adults, $10/children, free/under 2. 1 Franklin Park Rd, Dorchester. 617-541-5466. ZooNewEngland.org.

Race Against Extinction 5K – 11am. Runners and walkers, including animals, are invited to participate. Proceeds will be donated to The World Wildlife Fund and The Nature Conservatory. $25. Artesani Park, 1255 Soldiers Field Rd, Boston. TheRaceAgainstExtinction.org.

Blue Discoveries Family Day: Earth Day Celebration – 11am-3pm. Learn more about the blue planet through art, science and storytelling. Programs highlight aquarium favorites as well as often-overlooked inhabitants. Included with admission. $17.95/adults, $12.95/children 3-11. New England Aquarium, Central Wharf, Boston. 617-973-5200. NEAQ.org.

Natick Earth Day Festival – 11am-3pm. Rain date: Apr 28. Come together and discuss the issues of conservation, sustainability, land stewardship and volun- teer action. Includes kids’ activities, live music, vendors, demos and good food. Info & schedule: NatickEarthDay.org.

Earth Day at Wachusett Meadow – 1pm. Celebrate Earth Day by helping to maintain many miles of hiking trails, gardens and grounds. Preregistration would be helpful. Children under 16 must be accompanied by an adult. Free. Wachusett Meadow Wildlife Sanctuary, 13 Goodnow Rd, Princeton. 978-464-2712. MassAudubon.org.

Film Screening: The Story of Stuff – 7:30pm. This short animated documentary will change your life forever. UMass Amherst Campus, Campus Center Room 101. More info: umass.edu/events/earthday2013.

MONDAY, APRIL 22

Earth Day Festival 2013: Student Fair and Concert – 12-4pm. Variety of student organizations with interactive activities focused on taking action for a greener campus and planet. Also dance your way through the afternoon to live music. UMass Amherst Campus, Goodell Hall Lawn. More info: umass.edu/events/earthday2013.

Earth Dinner at The Fireplace – 5-10pm. Experience Earth Day dinner featuring all local food like fresh foraged mushrooms, Hillman Farm goat cheese, spring chicken pot pie, and sweet potato stew. A certified-green restaurant where they recycle, compost, do not use Styrofoam and have made a commitment to make four eco-friendly changes to the restaurant each year. Full menu available online. 1634 Beacon St, Brookline. 617-975-1900. FireplaceRest.com.

Earth Day 2013 Keynote Address: Annie Leonard and The Story of Stuff – 7pm. UMass Amherst Campus, Stockbridge Hall, Bowker Auditorium. More info: umass.edu/events/earthday2013.

Greening Our Community Series: Environmental Speaker Series – 7pm. Everything you’ve always wanted to know about trash and recycling, but  were afraid to ask. Presentation by Courtney Forrester and Elaine Gentile from Newton’s Department of Public Works. Newton Free Library, Druker Auditorium. GreenDecade.org/events.html#ess2.

SATURDAY, APRIL 27

Musketaquid Earth Day: River Ceremony, Parade & Festival – 10am-2pm. Musketaquid Arts and Environment’s 23rd annual Musketaquid Earth Day celebration, including a morning River Ceremony along the Concord River, a Parade with music and large puppets making its way from the river through Concord Center and ending with a Festival on the grounds of Emerson Umbrella Center for the Arts. Come and enjoy an abundance of art, entertainment, gastronomic delights and environmental awareness opportunities. Free. Emerson Umbrella Center for the Arts, 40 Stow St, Concord. 978-371-0820 x 213. EmersonUmbrella.org.

Watertown Bike Drive – 11am-3pm. Bring your old bikes to donate. No need to inflate the tires or even dust them off. Will provide a tax receipt for your donation, if you like. First Parish of Watertown, 35 Church St, Watertown. More info: BikesNotBombs.org/Bike-Drive/359.

SUNDAY, APRIL 28

NewtonSERVES Environmental Projects – 9am-4pm. A day of community service bringing together volunteers of all ages to complete tasks that benefit our City. Green Decade is sponsoring a swap & trade clothing event at The Newton Cultural Center, 1000 Commonwealth Ave. More info: 617-964-8567. To volunteer:  NewtonCommunityPride.org/NewtonSERVES.html.