Oneworld airlines have put East and West Coast USA cities to Europe on sale over the summer.
For example, fly from New York to Milan, Italy for only $358 roundtrip (see image below).
Miami/San Francisco/New York/Boston/Los Angeles/Washington DC/Philadelphia/San Jose/Santa Ana/Seattle/Atlanta/Orlando/Jacksonville/Tampa/Raleigh/Cincinnati/Salt Lake City/Las Vegas, USA
Prague, Czech Republic
(same as DEPART)
Availability from August 2017 to March 2018 (excluding Christmas & New Year)