. >> biodiverse city often argued to be important for the world's human populations because all of the medicineal plants and uses that we can put to it and fiber that it gives us and food that it gives us. while these are vital and important and worth literally hundreds of billions of dollars, the part that we also have to be able to communicate is the more spiritual sense of how important it is that we get to live side by side with all of these forms that have three billion years of history behind them and how tragic it would be not commercially and not in a utilitarian way but an emotional emotional, psychological spiritual way if we watch them one by one disappear. >> this is sort of a merger between art and science and advocacy in a funny way getting people to wake unand realize what is going on -- wake up and realize what is going on. so it is a memberorial trying to get us to interpret history and look to the past. they have always been about lacking at the past so we proceed forward and maybe don't commit the same mistakes. >> hi, i'm lawrence corn field. welcome to building san

how delicate ecosystems are and what an important role biodiversity plays in their ability to endure. just over 15 miles from the heart of panama city, and steps away from the panama canal, lies soberania national park a 55,000-acre rainforest that is just one of the many rainforests around the world being studied by tropical biologist bill laurance. dr. bill laurance: the focus of our research is, essentially how do humans affect tropical rainforests? about 40 million acres of tropical forest are being destroyed every year. that's about 80 football fields a minute and as a consequence we are seeing vast landscapes being denuded of forests. we are also seeing the original rainforest being chopped up into isolated islands or parcels. and this might seem like an ironic place to talk about it here because it seems like such a beautiful area. we are in the heart of panama in soberania national park but this is probably the future of much of tropical biology, because although it seems like a large area of rainforest over here we have bulldozers knocking down the forest. over in this direction we have slash-and-burn farming going on. we h

biodiversity's playground: mexican environmentalists keep a close watch on the gulf of california. so long, saigon: young architects compete to give hochi minh city a makeover. the deadly attack on tourists at the bardo museum in tunis is likely to lead to a dramatic tightening of security in north african countries. tunisia, which hosts the world social forum this week, is no exception. whilst rights groups warn against rolling back freedoms won during the tunisian revolution, the urgency of the need for new counter-terrorist measures is highlighted by the fact that tunisia has become the largest source of foreign fighters for the is militia in syria and iraq. many young people have left everything behind to respond to calls for a holy war. >> we've got hold of papers belonging to tunisian suicide attackers in iraq. after hesitating for a long time, one of their families has agreed to talk to us. we set off for jemaal, east of the capital, tunis. over 3 thousand tunisians have joined jihadist groups in syria and iraq. many of them come from desolate-looking villages and small towns like these. we're meeting the family of walid abdel hamit, a 35-