Loose Formation over the Elbe River

I'm flying OK-CPL, a Cessna 172RG, and my friend Al Waning is flying off my starboard wing in a Zephyr 2000 - was a beautiful day and a nice flight.

I actually didn't know the river I'm very often flying over and around was the famous Elbe until I made this post - in Czech it's called the Labe...