Enzo, dikes are the artificial "obstacles" alongside a river, lake or sea to prevent water flooding the surrounding land.
In my case it was a river dike. The dikes follow the river quite closely and that's why the roads on top have nice corners.
The fatal curve was a 3d gear one, that suddenly turned into a 2nd gear one... The road was rather narrow so I couldn't get the bike through anymore. I "jumped" off the 25 feet high dike involuntary and the bike luckily went on it's side and slid down the rocky surface. The rocker cover took most of the punishment and yes, that's a hole.
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