For our Geo Quiz we asked you about a freshly caught (in the Bosporus) and grilled mackerel sandwich served in a spectacular city. The answer is Istanbul, Turkey.

The mackerel sandwich is just one of the many treats that British food blogger Simon Majumdar mentions in his new book: Eat My Globe: One Year to Go Everywhere and Eat Everything.

We want to hear more sandwich ideas...the more the merrier.

What are the best (and worst) international sandwiches you've come across on your travels or at home? Where in the world did you encounter the tastiest or the most unusual sandwich?

Just to whet your appetite here's one of Simon Majumdar's favorites:

Simon's favorite British sandwich, the bacon batty:

And finally, where does the word "sandwich" come from anyway:

What are the best and worst international sandwiches you've come across on your travels or at home?