Live Maps came up with a new feature where you can find your Synths on the map. However, not easy to find whilst looking the first time for it.
To get the Photosynth collections, zoom into any area of interest, and select Collections and Explore Collections from the upper right menus.
On the left side you can choose from which collections the results should be displayed. The fourth icon provides a list of Synths from the region in the viewed area.