You can add every available map source to use on the main map of gaiagps.com by following these instructions.
1. Click the Layers icon
2. Then scroll to the bottom of the Layers list and click “Add Map Sources”
A List of map categories will appear on the left-hand side of the screen.
3. Click the category that suits your needs
4. Click the + to add the source (or the - to remove it)
5. You can also click the source listing to reveal a details screen containing information about the map source—if you check out these attributes, click the back arrow to return to the list.
6. Finally, click on the newly added map source in the Layers menu to select it as visible.