The Netherlands, owing to its intensive (and often controversial) farming techniques, is the largest supplier of bacon worldwide. Historically, however, the process of salting or curing slices of pork has been occurring across a number of European countries since as far back as the Saxon period in the first millennium A.D. Therefore, it's unclear whether any single nation can be attributed with the original "invention" of bacon.
The word "bacon" itself is English in origin, from the Middle English "bacoun." Although other European languages had similar words, such as the Old High German "bahho" or the Old French "bacun," they generally referred to any salted or cured cut of pork. Only the English word specifically referred to the belly cuts most widely known as bacon today (at least in the United States).
There are some other country-specific types of bacon to be aware of. For example, both Canadian and Irish bacon are traditionally loin cuts. In other countries, flavors are added to the meat before, during or after the curing process. In Hungary, before the pork is dry-cured, it is soaked in a solution of garlic, water and salt. After dry-curing, it is covered with cow's blood and paprika, then smoked.