Simon should have started this final leg of his journey by following the Tropic of Cancer through the far south of China, but Beijing officials declined to provide the team with visas, a reminder ...

The Tropic of Cancer skirts Cuba and, in Havana, Simon learns how city allotments have transformed agriculture in Cuba and countered the effects of the US trade embargo against the country.

The 22,835 mile long Tropic of Cancer marks the northern border of the Tropics, the region of the planet with both the richest natural biodiversity, and the greatest concentration of human suffering.