A Pittsburgher's Puzzle Crossword

This printable crossword puzzle on the topic of US Geography has 10 clues. Answers range from 5 to 19 letters long. This crossword is also available to download as a Microsoft Word document or a PDF.

Which Pittsburgh author wrote "Silent Spring?"
What famous Pittsburgh company invented ketchup?
What's the name of the Polish dumpling famous in Pittsburgh?
Myron Cope invented the Terrible ____________.
Which Pittsburgh river flows North?
Who created Daniel Striped Tiger?
Pittsburgh has 446 ______ - more than anywhere else in the world!
What vaccine was invented by Dr. Jonas Salk in Pittsburgh in 1950?
The "stars" in the Steeler logo are actually ________ borrowed from U.S. Steel's logo.
What famous building in NYC was built with Pittsburgh steel?