This was my first Photosynth and I didn't even know it! I just found out about PS a few days ago and tried it out on some photos from a recent trip to New Zealand in Feb.
This Synth is of the Aratiatia Gorge near Taupo, NZ. Perioducally the hydroelectric dam upstream will release large amounts of water from the dam for 30 minutes at a time, completely flooding the 15m deep gorge in a matter of minutes. The gorge is full in this Synth, it's pretty neat!