American Airlines has a low fare today at $443 round trip from San Francisco SFO to Zurich ZRH Switzerland. This deal is available for travel from September 2017 to early May 2018.
This American Airlines fare may not last through the day. Delta/SkyTeam shows $432 fares on Google Flights, however, these tickets are pricing over $1,000 now from SFO/SJC.
American Airlines (Finnair operated flights outbound)
San Francisco SFO – Helsinki HEL – Zurich ZRH – New York JFK – San Francisco SFO