I hate to say it, but, after the novelty wore off, I had this cliché moment of a Russian émigré abroad: I really missed black bread. I know it’s stupid, but I really missed it.
The biggest producer of rye by far is Germany, followed by Russia and Poland. Belarus, Denmark, China, Ukraine, Canada and the USA follow on more distant places.
Bread out of rye flour is very popular in Central, Eastern and Northern Europe.