A six-year-old London Underground superfan can recite the map by heart, has a Tube-themed bedroom and has visited all 272 stations.
Lewis Wing grew up near a Tube station in east London and became a passionate fan of the network from the age of three.
Now six, Lewis has just completed a tour of all 272 London Underground stations and hopes to have broken a World Record as the youngest person to complete the mission.
The Tube-loving schoolboy began his project with the help of mum Sheina Vasudevan, 46, and dad Peter Wing, 49, three years ago.
He visited the final two stations on his list - Battersea Power station and Nine Elms – on 20 September this year and is now waiting to hear from Guinness on whether he has broken the record.
Tube-mad Lewis said: "I like all trains. They're awesome."
His mum added: "We live near the Jubilee line depot so we can only assume his love blossomed from there.
"We were taking him on the Tube from three months old, and as soon as he could speak he was asking to go on the Tube."
The schoolboy began his mission aged three when he and his parents would catch the Tube to travel around the capital.
He became more and more interested and began requesting visits, as well as doing his own research, and even memorising the Tube map - which he can recite by heart.
Vasudevan began decorating her son's bedroom with Tube-themed decorations - from bedsheets and cushions to a hand-decorated clock - and his love grew from there.
They decided to take a snap of Lewis at every station they visited - and it soon spiralled into a challenge for him to visit every station in London.
When Lewis ticked off the final two stations on his tour had contacted Transport for London (TfL) to find out when they would be open.
Lewis said: "We went straight from school - it was the most tiring Monday of my life."
Reflecting on the past three years, he said his favourite stations were Sudbury Town "because it looks nice on the outside" and Stratford "because it looks nice on the inside".
Now he has completed his mission, the six-year-old is waiting to hear back from Guinness on whether he has become the youngest person ever to visit all 272 stations.
Read More From Yahoo News UK:
Vasudevan said: "He knows everything about it - we don't even question his knowledge anymore. Every morning he checks the Transport for London status report.
"Lots of six-year-olds sit around in front of the TV or a games console all day - so it's an interesting passion to have!
"Now Lewis has made it his mission to visit every national railway station - there are more than 2000.
"I think he can do that one for himself when he's a bit older!"
Watch: How to have an environmentally ethical Christmas