This HandyNotes plugin will show you on the map the co-ordinations of every area you need to discover for the Universal Explorer achievement.
Features and Toggling
You can go to addon config to toggle what you want to display or adjust the icon's size and alpha value.
You can also hide any specific node by right click on it on the worldmap.
Further, you can add all nodes to TomTom's waypoints by right click on any of the node icon on the worldmap.
Please comment any wrong co-ordinations and/or wrong map dots so I can change them to the right location.