Via Frequent Miler, you can fly coach from LOTS of US cities (big and small!) to Europe for ~$530+, with this huge Delta sale.
I found a flight from Atlanta to Amsterdam leaving November 8, 2017, and returning November 15, 2017, for ~$538. And a flight departing Minneapolis on August 11, 2017, returning from Paris August 18, 2017, for ~$597.
These sale fares are valid for travel from July 2017 through May 2018. Meaning you can visit Europe for cheap this summer, or plan fly for less this fall and winter!
Here are the details. And how to search for deals from your city!