A man running the length of Africa is eyeing the most difficult part of the challenge - crossing the Sahara Desert.
Russell Cook, from Worthing, West Sussex, had originally planned to complete 360 marathons in 240 days.
After complications with his visas, health scares, geopolitical issues and an armed robbery, the 26-year-old was forced to extend the challenge.
On day 273, Mr Cook said he was "sizing up the Sahara" for the final leg of the mission.
"We've got a difficult stretch to manoeuvre. One of those reasons is because the Sahara Desert is really big, famously has no water and is very hot," he said.
"Another thing to add into that issue is that there are some quite difficult geopolitical issues to resolve in that region.
"We have to cross from Mauritania to Algeria on foot, which as far as we can see from research, hasn't been done by foreigners in a very long time."
Mr Cook, nicknamed "Hardest Geezer", said he had attempted to contact tourism boards and government representatives in Algeria to "help smooth that situation over".
The extreme challenge began at South Africa's most southerly point on 22 April and will finish at Tunisia's most northerly point.
Mr Cook had originally aimed to cover 14,500km (9,320 miles) during the challenge, crossing 16 borders, but extended the challenge due to complications.
Speaking from Senegal, Mr Cook said he did not expect any difficulties from the wildlife in the Sahara Desert.
"Luckily for me, all the big ones seem to have heard rumours of a mad ginger man running through the continent, and they have just deserted at all costs," he added.
The challenge is in aid of The Running Charity, having raised £131,898 so far.