Dr Andrew Murray, who works in Edinburgh, crossed the finishing line in Sydney, Australia yesterday after an epic round-the-world run.
Dr Murray, who is the Scottish Government's physical activity tsar, set off on his first 50km (31 miles) ultra marathon in Antarctica last Thursday.
He then travelled on to South America, where he repeated the feat in Punta Arenas, Patagonia, before jetting on to complete the North American leg of his challenge in Atlanta, Georgia and the European stint in London.
The remaining marathons took him around the Pyramids in Cairo, then onto Dubai and finally Sydney.
Dr Murray is aiming to raise a total of £10,000 for the Scottish Association for Mental Health.
He said the experience had been "fantastic".
Last year he ran 2659 miles –averaging more than 34 miles a day – from Scotland to the Sahara in 77 days.