Our presenters look back on their wild adventures with some of nature's heavyweights across North America.The continent has a very special place in Gordon Buchanan's heart. He once spent a year in the vast forests of Minnesota, getting to know a family of wild black bears. For Chris Packham, meanwhile, it's North America's coastal regions that are its greatest asset. He recalls a magical moment when a sperm whale popped up alongside his boat, as well as the time he got a little too close for comfort to a grey whale's blowhole.Liz Bonnin recounts an even more bizarre adventure in North America, when she filmed alligators in Florida during their breeding season, while wildlife cameraman Colin Stafford-Johnson tells us about what he describes as one of his most luxurious shoots in North America, filming sea otters in the busy port of Monterey Bay.Finally, Steve Backshall has had some of his most special filming moments in North America, including his time swimming with sperm whales in the Caribbean and seeing their immense intelligence in action.