On top of the basemap one or more overlays can be shown, such as street address numbers and the Cyclorama recording locations. Press the layer icon in the menu in the bottom of the map viewer and choose Overlays to view and activate the available overlays.
You can change the overlay opacity through the visibility icon in the menu (right of the layer icon). Drag the transparency slider to the desired value to change the opacity of the overlays.
Viewer tools, such as the zoom bar and the scale bar, can also be switched on and off through the layer icon. Choose Viewer and select the items you wish to see in the map viewer.
Note: some overlays are shown in Cycloramas as well. From the Overlays menu in the map viewer you will toggle their visibility, too.