The pedestal of the Brooklyn Bridge and the plaza beneath it become a window into the deep ocean this Friday and Saturday night. “AQUA COSMOS: The Hudson Canyon,” an 18-minute projection by multimedia artist Anita Glesta, plays on a loop across the bridge and the ground around it — a free, walk-up event with no tickets and no reservation.

  • When: Friday, Sept. 25 and Saturday, Sept. 26, 7-10 p.m. The film loops for the full three hours, so arriving late is fine.
  • Where: Emily Warren Roebling Plaza, Brooklyn Bridge Park — the DUMBO side, directly under the bridge. Free park entry, open until 1 a.m.
  • Cost: nothing. Brooklyn Bridge Park’s listing calls it “a free public walk-up event.” Gather and watch.
  • What it is: a monumental projection built with the Wildlife Conservation Society, presented through the NYC Department of Transportation’s art program, with partners including ArtW.
  • What you’re looking at: the Hudson Canyon, the largest submarine canyon on the Atlantic Coast, about 100 miles southeast of the city and comparable in scale to the Grand Canyon. It holds whales, sea turtles, sharks, tuna, cold-water corals, and the species that support local fisheries.
  • The archive layer: the piece marks the 101st anniversary of the 1925 Arcturus Expedition, the first real survey of the canyon. No camera could yet photograph underwater life, so the record was made by illustrators — six women on board worked as scientists and artists, and their drawings are paired here with new NOAA deep-sea footage, whale vocalizations recorded by WCS’s New York Bight team, and Glesta’s own hand-drawn animation.

The obvious move is to go Friday, walk the plaza during one loop, then catch it again from a different angle — the projection hits the bridge structure and the ground separately, and they don’t read the same way from both.

There is a second reason the piece exists. WCS has been pushing since 2016 to have the canyon designated a National Marine Sanctuary, which would be the first one off the coasts of New York and New Jersey. Glesta learned about the canyon at a WCS talk where nobody in a New York City audience raised a hand when asked if they had heard of it. Seeing it is the whole point: an ecosystem this close to the city that most of us have never once pictured.