The Green Tree Tavern is the oldest verified vertical log building in Ste. Genevieve. Officially dated to 1790 by dendrochronology studies, this “poteau sur sole” (post on sill) vertical log construction was built by the French Canadian Nicolas Janis. This impressive structure has also been used as an inn, a tobacco store, and the first Masonic Lodge in Missouri. The Green Tree is now part of the National Park Service. Open seasonally.