Do you “collect” Boundary Stones marking the former border of the District of Columbia? Here’s one you won’t want to miss: No. 9 SW, in the Falls Church portion of Benjamin Banneker Park. It’s just steps from where Tree Steward trainees will be planting 600 saplings on Saturday, Nov. 10 and Wednesday, Nov. 14. Come out, help plant trees, and collect a Boundary Stone!