If you want to have an Admin(s) and/or Sub-Admin(s) take a final look at all of the submitted approved events and have them give a final approval, go to Settings > Advanced > General > Event Creation to enable the Final Approval process, as shown below.
AFTER you enable this extra layer of approval, you must also give permissions to an Admin(s) and or Sub-Admin(s) to be the Final Approver by going to Settings > Basic > Users, editing a user and checking the box for "Can user Final Approve Events?" and SAVE. The final approver will be able to final approve events based on their location permissions.
When selected and after all Sub-Admins and Admins have approved their areas of responsibility for an event, the Final Approver will be able to see the event on their dashboard (Final Approval grid) to approve or decline, based on their location permissions.