All events are in Brooklyn unless noted and most are free.
Saturday: Beneath the Ice: Immersion Dome installation takes visitors on a deep dive into Antarctic waters to explore a hidden world beneath the ice, 10 am to 4 pm, daily till May 27, free with museum admission and members at American Museum of Natural History, Central Park West at West 79th Street, NY. Brooklyn’s Open House, meet Borough President Adams and his team, and get a tour of Borough Hall, 6–9 pm, Borough Hall, 209 Joralemon St. between Court and Adams Streets. Wall climbing under the Manhattan Bridge http://dumbo.thecliffsclimbing.com/
Saturday and Sunday: Green Festival Expo, dozens of experts and presenters providing materials on how you can live a better greener life. Loads of children’s activities including an Interactive Sustainability learning Game; Growums Captain Eggplant teaches gardening tips to kids. Dr. Oz’s Health Corps provides lessons on sugary drinks; the Swim Strong Foundation hosts water activities, $10 per day ($19 weekend pass), both days 10 am to 5 pm, Jacob Javits Convention Center, 655 W. 34th St. and 11th Avenue, NY. Show Up! The work unites ballerinas, B-Boys, modern dancers, and more under an eclectic soundtrack that includes classical, Jazz, Bluegrass, Hip Hop, and contemporary music, as well as live African drumming, $32.50, both days 3 pm and 6 pm, Kumble Theater at Long Island University, DeKalb and Flatbush Avenues. UniverSoul Circus with circus arts, theater and music, Tuesdays–Sundays, 7 pm until Sunday, April 24, 20–$35, Aviator Sports and Events Center, 3159 Flatbush Ave. in Floyd Bennett Field. The Photography Show is one of the biggest fine-art photography shows in the world, featuring museum-quality work from 19th-century photos to contemporary images at the Park Avenue Armory
643 Park Ave E. 67th St. New York Travel Festival, workshops, discussions and presentations from travel industry professionals, 10 am–6 pm, $35–$160, St. Francis College, 180 Remsen St. between Court and Clinton Streets. Earth Day events http://earthdayinitiative.org/. http://www.nycgovparks.org/events/earth_and_arbor_days.
Sunday: National Grid Earth Day Celebration at BC, live music, arts and crafts, and street performers at this free community festival, where interactive family activities highlight the need to create a more sustainable future and care for the earth, 3 pm, Brooklyn Center for the Performing Arts at Brooklyn College, Whitman Theater
Two Prospect Park events at the same time: Earth Day fun activities from fishing lessons to how to keep the park healthy and a performance and parade – Bash the Trash, where marchers will make instruments out of recycled materials and then jam out with Bash The Trash, 1 pm to 4 pm, Prospect Park Audubon Center, enter park at Lincoln Road and Ocean Avenue. Bernie Sanders Rally 3 pm, along with Congresswoman Tulsi Gabbard and guests Danny Devito, Justin Long and the band Grizzly Bear, Prospect Park, Ocean Avenue at Lincoln Road, near the boathouse.
Walk MS – NYC, 9 am–1:30 pm, registration fees, to support MS research; Music artist David Osmond performs. Walkers meet at Pier 26 and walk along the park, enjoying views of the Hudson and New Jersey. Walk begins at 10:15 am, Pier 26. West and North Moore Streets. Marilyn McCoo & Billy Davis, Jr. (oldies music), $45, 3 pm, Queensborough Performing Arts Center, 222-05 56th Ave, Queens.
More ongoing: Tribeca Film Festival till April 24, https://tribecafilm.com/.
The Titanosaur, the cast of the largest dinosaur that ever walked the earth is now on exhibit and weighed about 70 tons, 11 am to 5 pm, daily, till Jan 31, American Museum of Natural History, Central Park West at West 79th Street, NY.