This free open-air exhibition of vast aerial colour photographs in the gardens of London's Natural History Museum is well worth seeing, and the extension of its run into the autumn will give more of us a chance to do so. Humanists who were moved by the photographs of earth from space (so small, so blue, so beautiful), will get a different kind of pleasure, and a more mixed one, from these 'state of the planet' pictures taken by French photographer Yann Arthus-Bertrand. The views are much closer, and they have a more obviously provocative intention: to remind us of the almost incredible beauty of Earth (and it is still strikingly beautiful, particularly, perhaps, seen from this unusual angle) and the damage we are doing to it. Humankind leaves its mark almost everywhere, though as represented in the exhibition, the mark is not always an ugly blot: rugs laid out in a Moroccan market, cotton bales piled like giant cauliflowers, the intricate wavy rows of mountain terraces, even the windows and balconies of crowded third world tenements, have a pattern and charm of their own, though a little thought reminds one of the punishingly hard work behind the rugs and terraced plots and cotton bales, and the noise and stink of slums that are missing from a mono-sensory photo.

Arthus-Bertrand took years to create this collection, and today expresses his pleasure in finding it in great demand all over the world. "What is extraordinary about this project is it is making the planet better known," he says. "The best present of this adventure is the feeling of having done something useful." And useful it is — to show us things that most of us would never otherwise see and to remind us all of the beauty and fragility of the eco-system we inhabit. A good outing for children too.

The exhibition, Earth from the Air, can be visited at the Natural History Museum every day until 8pm, throughout the summer. See also: