Mr Summerfield, 40, visited 23 countries in four continents after setting off from 0 degrees longitude at the Greenwich Observatory.
He averaged 11mph and covered up to 40 miles a day as he cycled across Europe into Turkey before riding through Australia and New Zealand.
In Australia, he raced in the Penny Farthing World Championships and came second in one of the 'novice' categories.
From China - where he cycled without the correct permits - he managed to sneak across the border into Tibet despite his bike's giant front wheel that is 1.2 metres in diameter.
He then took in India and Nepal, where he crossed the Himalayas at 17,000ft (5,200m) and made it to Everest base camp.
Mr Summerfield, who was forced to abort two previous attempts through injury, next rode through south-east Asia, the USA and Canada before heading for home.
Believe it or not, he is not the first to ride around the world on a penny farthing! Thomas Stevens did it in 1887. Link -via Arbroath
(image credit: Tim Stewart/TSW)