Around 8,500 cyclists prevented motorists from using a stretch of Germany's autobahn, during a protest calling for better public transport and cycle lanes.
The demonstration took place between Frankfurt and Wiesbaden - a distance of 40km (25 miles).
It was organised by Verkehrswende Hessen - a group seeking to make transport in the German state of Hesse climate-neutral by 2030.
Okay. I'm impressed.
If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.