The celebration came to be called Thanksgiving Day in Canada and the United States of America. Elsewhere, it was called the harvest festival. Celebration of the harvest was common throughout Europe. The dates may have differed. But different peoples shared a common reason for the harvest celebrations and a more or less common type of food to be served. So a German fare would have fit in with a general European fare of wild animal meat, harvested grains and vegetables, and baked breads and desserts.
They did not celebrate Thanksgiving.
they didn't eat clams at the first thanksgiving
Thanksgiving is not known in Romania.
Thanksgiving is celebrated in North American, not in Poland.
Germans eat a lot...
A tradition is for turkey to be ate on Thanksgiving.
There is not Thanksgiving in France It is an American and Canadian holiday
Thanksgiving is only celebrated in North America.
We usually don't celebrate Thanksgiving in Norway...
In Germany and Austria it is the 1st Sunday in October.
There is no custom. Of course, there are natives in the north that eat seals, and might eat a seal on Thanksgiving, coincidentally.
Your choice entirely.