Five years in production and backed by a reported $25 million budget, this BBC Natural History Unit series sets out to film the planet's remaining wild places before they change beyond recognition. Eleven episodes move habitat by habitat: the poles, mountains, deserts, caves, fresh water, shallow seas, and the open ocean depths, each one built around behavior rarely caught on camera, from Himalayan snow leopards stalking prey to great white sharks breaching for seals off South Africa. Aerial photography and long-lens tracking shots, some of the first of their kind at this scale, let the crews follow migrations across entire continents without cutting away. David Attenborough narrates, keeping the focus on what the animals are doing and why, rather than on the difficulty of filming it, though behind-the-scenes footage included with several episodes shows crews waiting weeks in blinds or descending into cave systems for a single shot. The scope is the point: an attempt to catalog the natural world's extremes, from the driest deserts to the deepest ocean trenches, in one connected series.