During his climb up the Gherkin today, Lloyd Scott MBE is wearing at 1940s diving suit that weighs 140lbs, or 10 stone.
The antique suit, complete with solid copper helmet, means that the cumulative weight Lloyd will lift during his climb is 66 metric tons.
It's not the first time Lloyd has been seen in one of these suits however. He's completed a number of marathons in one, including the London Marathon in 2002 when he broke the record for the slowest time, taking almost six days to complete it.
He was also the first person to complete the 2012 Olympic Marathon Route, again wearing one of the suits. He was barred from competing in the actual race as it was ruled that competitors have to finish on the same day the race starts.
More top news
CCTV and images show man suspected of trying to set the north London mosque alight in alleged Islamophobic hate crime
Detectives investigating a man's body washed up on the shores of the river have arrested a second man on suspicion of murder.
Keepers have the celebrating the arrival of the western lowland gorilla to 22-year-old mother Effie in captivity at the zoo.