C2A lets you position a landmark (a cross displayed on the screen) on an object in the map. To do that, just position the mouse cusor on an object, make a right mouse click and select Set Landmark. This landmark lets you quickly identify an object on the map, and to go to it quickly with the command Go to Landmark in the Edit menu. This is what an object with a landmark on it looks like:
The landmark can be deleted with the command Clear Landmark in the Edit menu.