הגדולים ביותר

Crocodiles surround this beautiful island. Dr. Brady Barr and the University of Florida teach some capture techniques.

Diego reports from one of Tehran's biggest events: Quran Idol, where people compete at reading from the Quran.

The Russian Arctic, extreme habitat and haven for polar bears, lemmings, arctic foxes and walruses.

A wood-powered pick-up truck takes to the streets of London with modern-day activists, Trees for Cities.

Diego mingles with graffiti artists and dodges bullets to find what unites the extreme rich and poor in São Paulo.