Have to admit, I had never heard about it, either.
The question, then, is why not?
Strange. Even with the political tensions that clearly exist between the two countries, I would have thought that we would at least have heard of this.
Here is the link:
Tear Drop “A Gift From the People of Russia to the USA”. Why were we not told about Tear Drop? By Michael Aydinian, August 15, 2015: