"We had been looking for the elusive narwhal for weeks on our journey through the Northwest Passage in the Canadian Arctic," says Tennant. "Through binoculars we spotted movements near the face of a glacier and we quickly launched our drone to investigate the scene from above. The view we saw from the sky was truly mesmerising. As the pod swam slowly through the silt water, they would gently weave the most beautiful abstract patterns. These ghost-like markings were transient and followed the narwhal as they glided through the bay. It felt like a window into another world."