[09/08/2021 @ 01:08 PM] Price drop to $267-$534. Was $348-$538. Note that Italy, Spain, Denmark, Netherlands, Belgium, Sweden, and Norway have increased travel restrictions.
[09/09/2021 @ 01:27 PM] Greece plans to continue to allow US tourists until at least the end of their Tourist Season, per Tourism Minister.
Oneworld, SkyTeam, and Star Alliance carriers have flights to Europe on sale for $267-$534. Flight dates are mostly between September and February of next year. Smaller airports will have more stops or worse routing than major airports.
Expect prices to shift around +/- 10% as the deal ages.
Be sure to research your destination before finalizing any travel plans. While most EU member states have not made any changes to travel restrictions, several have (see links in Timestamp).
Click for more details and booking links Cheap Flights: Chicago and Milwaukee to Europe $267-$534 r/t [September-February] – Various