Will the plants reap the benefit of teardrops as well as raindrops as Charlie, Tommy, Kirsty and Will face their last ever challenge? The team have three days to transform an empty plot outside the British Museum into a horticultural project symbolising Africa's diversity. The planting aims to reflect the desert lands of North Africa, the Tropics and the temperate regions to the south, while a water sculpture by artist Sokari Douglas Camp captures the continent's vibrancy and drama.

Africa round-up: 28; The Inside Story: page 96