The Earth Day Historical Heritage Walking Tour with Sour Lake Lion Mary Catherine Johnston is scheduled for 10 a.m. to 11:20 a.m. Friday, April 21, the day before Earth Day.The tour will begin in front of the Sour Lake Fire Station at 711 Sixth Street and end at Lions Park Pavilion on S. Ann Street across from the Sour Lake Community Center and Library.To make reservations, go to mathicket@gmail.com.