tl;dr: In 2003, São Paulo resident Hélio Silva began planting Atlantic Forest seedlings in a degraded, trash-filled area along the Tiquatira stream, funding it himself. Despite a local businessman twice destroying his saplings (200, then 400), he persisted and eventually gained community support. By 2007, the city officially designated it São Paulo's first linear park; today it spans 320,000 m² with 32,000 trees across 160 species.