Helio da Silva, a retired business executive from Brazil, single-handedly planted over 41,000 trees in his hometown of Sao Paolo over the last two decades.

Flying over the Brazilian metropolis of Sao Paolo, it’s tough to miss the 3.2-kilometers-long and 100-meter-wide green strip of trees wedged between two of the city’s busiest roads. It is known as Tiquatira Linear Park, and it is the work of a single man who worked tirelessly for over 20 years in order to transform a previously dilapidated area into an actual jungle within the urban jungle that is Sao Paolo. Originally from the town of Promissao, about 500km from Sao Paulo, Helio da Silva was a successful business executive for many years, but after retiring, he took it upon himself to transform the degraded banks of the Tiquatira River into a green oasis for his community. He started planting trees there in 20023 and hasn’t stopped since.