Actors Shane Richie and Josie Lawrence are entrusted with the last leg of the relay.
Torchwood star John Barrowman and TV presenter Myleene Klass race across southern America.
The celebrity relay continues with Breakfast presenters Bill Turnbull and Louise Minchin.
The celebrity relay continues with Matt Baker and Julia Bradbury from Countryfile.
Apprentice stars Nick Hewer and Saira Khan take the baton from Turkey to Kazakhstan.
In the first leg, Frank Skinner and Lee Mack travel from London's Reform Club to Turkey.