This is the Earth - our planet, home to millions of different species, but only one species dominates everything - human beings. There are nearly sev… - David Attenborough

The island is immense. It's 1,000 miles long, if you discount a narrow arm of sea that crosses it in the middle, and it contains mountains over 12,000 feet high. It's New Zealand. The first land-living mammals to get here were human beings and they didn't arrive until a mere 1,500 years ago. So here you can glimpse what the world would have been like if the birds had won that battle with the early mammals and now ruled the Earth, for here they once did.

The Roman public's thirst for blood and pleasure in witnessing pain seems to have been unquenchable and without limit. The caged animals were kept in dungeons below the main arena. The terrified animals in their cages were hoisted up from this pit. And not only animals, human beings too, criminals, slaves and prisoners of war. And here in this arena they were set one upon the other to provide the crowd with spectacles of the most appalling carnage. It still continues to this day in Spain.

I'm very aware that this programme may be regarded as bleak or depressing - an increasing population with an ever decreasing supply of resources – but humans have capabilities that animals don't: to think rationally; to study; to plan ahead. The number of people on the planet depends on the personal decisions we each make regarding the number of children we have even setting aside the moral responsibility we have to protect other species, if we continue to damage our ecosystem, we damage ourselves. Its clear that we'll have to change the way that we live and use our resources. We're at a crossroads where we can chose to cooperate or carry on regardless. Can our intelligence save us? I hope so. m46s24-m47s15