The carpenter Jaako Leppänen is remembered all as the builder of the wooden church at Petajavesi. It is one of the few Finnish properties to have been placed on UNESCO's Word Heritage list. During the Petajavesi years, Jaakko Leppanen was already an elderly man, having been born during the Great Nothern War. Before coming to Petajavesi, Leppänen worked as a joiner at Lannavesi in Saarijarvi.