After surviving the most dangerous region in Colombia, Simon is nearly swallowed by a tidal wave in Brazil. The final leg of Simon Reeve's series starts in the Galapagos Islands. The islands might look gorgeous, but Simon discovers there are concerns that the 100,000 tourists who visit each year are threatening the fragile ecosystem. Fishermen in the Galapagos also claim they are not being given a chance to earn a decent living on the island, and have allegedly killed several giant Galapagos tortoises in protest. In the Ecuadorian capital, Quito, Simon makes the difficult climb to the top of El Reventador volcano, known as 'The Exploder'. A local scientist explains that Quito is the world's most at-risk city, due to volcanic activity created by geological pressures on either side of the equator. Simon passes through the most dangerous and lawless area of Colombia, where government forces regularly battle guerrilla rebels. A trek through the jungle reveals endangered animals and a remote Indian tribe with a sacred equatorial monument to the 'middle of the world'. In Brazil, speedboats take Simon along the Amazon River, through vast untouched tracts of the Amazon rainforest, to meet remote indigenous tribes now suffering unemployment and alcoholism. Much of the rainforest in the equator zone in western Brazil is still pristine, and there are numerous tribes living in complete isolation. Several have never had contact with the outside world. However, loggers and farmers are slowly moving in their direction from the south. Simon races east across Brazil to his final destination in time for the Pororoca wave, a unique natural phenomenon: a tide that coincides with a full moon sends a mini-tsunami up the Amazon tributaries. Experienced surfers (and complete amateur Simon) have one chance to ride the tidal bore before returning to town for a Samba Carnival along the Equator. But he and the boat crew forget that the wave happens twice a day, and their large boat is nearly capsized ...